By: Silvy Park

What is it?

• 

Hemochromatosis is a disorder in which the body stores too much iron (excess iron is not effectively removed from the blood). This is dangerous because too much iron is toxic and can poison your organs, resulting in severe organ failure and even death. Common symptoms include joint pain, fatigue, general weakness, weight loss, and stomach pain. The prognosis for people who have hemochromatosis depends on how much organ damage they have upon diagnosis. Therefore, early diagnosis is important for treatment. Moreover, Hereditary Hemochromatosis, or HH, is more common in Caucasian men. In fact, some research highlights that men are five times more likely to have it than women. 

The HFE Gene

The HFE gene is responsible for the genetic variation. It makes sense that the variations change the gene expression because the gene encodes for the hemochromatosis protein in humans and regulates iron absorption by regulating the interaction of the transferrin receptor with transferrin.

There are two main alleles in the HFE gene: rs1800562, also known as C282Y (risk genotype AA), which can cause a serious form of Hemochromatosis and rs1799945, also known as H63D (risk genotype GG), which can cause a mild form of Hemochromatosis [4]. 

Besides Type 1 HH, there are also Type 2 and Type 3 hemochromatosis, which are both also recessively inherited. Type 2 hemochromatosis results from mutations in the HJV or HAMP genes, while Type 3 hemochromatosis results from mutations in the TFR2 gene.

Pros and Cons: Why Should You Get Tested? 

Pros: 

• Hemochromatosis is one of the most common hereditary disorders in the United States, with about 1 in every 8-12 Caucasians in the United States being a carrier (one copy of the HFE defect) and about 5 in every 1,000 to have two copies of the HFE defect [3]. 
• Genetic testing can show whether you have one or two recessive HFE gene(s). 
• You can be prepared. Symptoms of hemochromatosis usually appear in men between the ages of 30 and 50. Symptoms often do not appear in women until after age 50 or after menopause, most likely because women lose iron from the blood loss of menstruation and childbirth.
• Getting a test done can help a person avoid serious symptoms of the disorder. If left untreated, the disorder can lead to cirrhosis of the liver, diabetes, hypermelanotic pigmentation of the skin, heart disease, liver cancer, depression, and fatigue, all of which can be easily avoided if a person is treated beforehand [4].
• HH is a candidate for genetic screening because the mutations associated with HH are present at birth, even though symptoms do not show up until adulthood. 
• If people who have hemochromatosis want offspring, genetic testing and counseling can determine the likelihood of the parents passing the HH genes on to their children.

Cons:

• Having two copies of the Hereditary Hemochromatosis alleles will not necessarily cause the disorder.
• Tests cannot predict whether you’ll develop signs and symptoms of hemochromatosis. Therefore, there is no strong evidence supporting a connection between these variations and the trait in questions [1]. 
• The test is relatively expensive, considering that the odds of actually having Hereditary Hemochromatosis and its extreme symptoms are very unlikely.

Testing

A recommended test for hemochromatosis is an iron panel of blood tests. A complete iron panel typically includes the following: Ferritin, Transferrin Saturation %, Serum Iron, and TIBC/UIBC [5]. DNA genetic testing can be done by collecting calls from the inside of your mouth using a cotton swab or drawing blood from an arm vein [3]. Cost is usually around $100 to analyze the HFE gene. A comprehensive genetic test that analyzes five genes associated with HH is shown below. Cost varies but is usually less than $100.

Q & A:

If someone in the family has already tested positive, what are the chances that a child, nephew, aunt will test positive?

Most people who have HH inherit two hemochromatosis genes, one from each parent. Having a person in your family with HH does increase your chance of having HH as well, but not everyone who inherits the genes develops symptoms or complications of the disease. 

What should be your plan if you test positive or negative? 

HH can be easily treated by phlebotomy or regular donation of blood to reduce blood iron levels. Iron chelation therapy uses medicine to remove excess iron from your body. However, those with two copies of Hereditary Hemochromatosis who are diagnosed as not having Hemochromatosis should still familiarize themselves with the symptoms in case it develops later.

What type of screening is recommend if you do test positive?

If you test positive for the HFE gene mutation, it is recommended that you test for Hemochromatosis through an iron panel of blood tests.

What type of environmental factors should you consider changing in response to a positive test?

Keeping a low-iron diet can help a lot. For example, avoid taking iron pills and limit the intake of Vitamin C.

References

[1] Adams, P. C. (2002). Screening for Hemochromatosis. BC Medical Journal, 44. Retrieved from https://www.bcmj.org/articles/screening-hemochromatosis—should-we-do-last-test-first

[2] Chandrasekharan, S., Pitlick, E., Heaney, C., & Cook-Deegan, R. (2010). Impact of gene patents and licensing practices on access to genetic testing for hereditary hemochromatosis. Genetics in Medicine, 12. doi: 10.1097/gim.0b013e3181d7acb0

[3] Hemochromatosis. (n.d.). Retrieved from https://www.nhlbi.nih.gov/health-topics/hemochromatosis.

[4] Hemochromatosis. (2018, May 21). Retrieved from https://www.snpedia.com/index.php/Hemochromatosis.

[5] Lewis, E. (2019, July 25). Hemochromatosis Lab Testing. Retrieved from https://hemochromatosishelp.com/hemochromatosis-testing/.

The rs7216389 SNP is associated with susceptibility to Childhood Asthma. Childhood Asthma is when a child’s lungs and airways become easily inflamed when they are exposed to certain triggers, such as exposure to pollen or respiratory infections. Symptoms of asthma include “shortness of breath, chest tightness or pain, trouble sleeping caused by shortness of breath, coughing or wheezing, whistling or wheezing sound when exhaling (wheezing is a common sign of asthma in children), or coughing or wheezing attacks that are worsened by a respiratory virus, such as a cold or the flu.” (Mayo Clinic) The genotype CC gives the patient 0.69x lower risk of Childhood Asthma. The genotype CT gives the patient a normal risk for Childhood Asthma. The genotype TT gives the patient a 1.5x increased risk for Childhood Asthma. Asthma is the most chronic condition among children, affecting about 6.1 million kids under the age of 18. The protein IL-13 (interleukin-13) causes changes in the airways of asthma patients. It is a naturally occurring protein made by the IL13 gene, and it leads to inflammation, which in this case would be the lungs and airways. It does not alter any traits.

Any child should be tested for asthma, but children of parents who have asthma are more at risk and should be tested for rs7216389. If they have this, they will be more at risk to develop childhood asthma. To test this, I would recommend Single Gene DNA sequencing which should only cost around $10. The normal trait in question would be a CT genotype while a higher risk of the disease would be a TT genotype, and a lower than normal risk would be a CC genotype. There is evidence supporting the variations and the risk of Childhood Asthma two studies that both showed a correlation between the TT genotype and a higher risk of developing Childhood Asthma. Everyone has a risk of developing asthma based on environmental factors. About 1 in every 12 children develops asthma. However, having the TT genotype for the SNP rs7216389 gives children a larger risk for developing Asthma, which is shown through more kids with the TT genotype developing asthma than the other genotypes.

There is not much risk to having the single gene DNA sequencing test done. However, someone may not want to get the test done since it only finds whether you are more at risk to develop childhood asthma. Even if someone tests positive for the TT genotype, they may still never develop childhood asthma. Also, it is not 100% proven yet that the TT genotype with the rs7216389 SNP actually leads to a higher risk of Childhood Asthma.

There are no genetic privacy concerns that the consumer may want to consider. A potential downside of being tested is that even if you test negative, you can still develop Childhood Asthma. There are no studies that look at reactions to testing positive in this case.

If a family member tests positive for this, the child has a higher chance for testing positive. If a child tests positive for this, their plan should be to look out for symptoms of Asthma to be on top of it in case of an onset of severe Asthma. If someone tests positive for this, I would recommend telling your doctor that you tested positive for a gene that leads to a higher risk of developing Asthma. Then, the doctor may want to test for asthma in the patient. If someone does test positive for asthma, they should reduce the time that they spend doing the things that lead to their asthma symptoms, such as exercise, but not necessarily eliminate it from their daily lives. When doing these things, such as exercising, they need to watch for changes in breathing and for wheezing to prevent an asthma attack from happening before it actually happens.

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Words Cited

Centers for Disease Control and Prevention. (2019, October 19). Asthma. Retrieved from https://www.cdc.gov/asthma/default.htm.

Mayo Clinic. (2018, June 4). Asthma. Retrieved from https://www.mayoclinic.org/diseases-conditions/asthma/symptoms-causes/syc-20369653.

Science Daily. (2011, March 22). Protein associated with allergic response causes airway changes in asthma patients. Retrieved from https://www.sciencedaily.com/releases/2011/03/110322151256.htm#:~:targetText=Summary%3A,according%20to%20a%20new%20study. 

SNPedia. (2019, July 3). rs7216389. Retrieved from https://www.snpedia.com/index.php/Rs7216389.

What is alcoholism?

The definition of alcoholism is “an addiction to the consumption of alcoholic liquor or the mental illness and compulsive behavior resulting from alcohol dependency” (google). This “dependency” on alcohol increases health risks greatly in comparison to those who are not dependent on alcohol. The National Institute of Health (NIH) shares statistics saying 5.7% of people 18 and older have AUD (alcohol use disorder), while 1.8% of children 12-17 have AUD. NIH also shares the risks of alcohol disorders: liver failure, strokes, cardiomyopathy, and much more.

According to SNPedia, there are 6 main genes & 7 SNPs that impact likelihood of alcohol dependency. The six genes include: GHS-R1A, GABRA 2, SLC6A4, OPRM1, D2, and SLC6A3. Many of these genes are genes expressed in the brain, opioid receptor, dopamine receptor, dopamine transporter gene, neurotransmitter transporter. This is part of the reason alcoholism is a very dangerous disease and hard to overcome.

Testing for Alcoholism

There are many reasons people would want to get tested for increased alcoholism related traits. SNPs such as rs27048 and rs27072 are associated with very dangerous symptoms, such as seizures. For these two SNPs, I would recommend a SNP test, which would cost around $200. If one wants to see if they simply have increased chances for alcoholism, they would need a whole genome sequence testing, which costs hundreds of dollars. If one wants one specific test for the most common allele, they can also do that by single-gene testing. Personally, I would only recommend using whole genome sequencing if you have increased likelihood of severe symptoms or if alcoholism runs in your family. Ultimately, there is a strong correlation between alcoholism and genetics.

Downsides of Testing

Taking a whole genome sequencing test can inform one of many different variations within all of their genes. This can potentially lead them to variations in alleles they didn’t affect that increase risks for other diseases. Limitations for this test are that not all variations of the alleles increase the risk by a substantial amount; therefore, there is a possibility $1000+ may allow you to find something out that does not matter too much.  There are a few disadvantages of this test. First, the role of most of the genes in the human genome is still unknown or incompletely understood. Therefore, a lot of the “information” found in a human genome sequence is unusable at present. Also, an individual’s genome may contain information that they do not want to know. For example, a patient could undergo genome sequencing in order to determine the most effective treatment plan for high cholesterol. In the process, researchers could potentially find an allele that relates to a terminal illness with no effective treatment.

Ethical Concerns

Considering how vast the information in a whole genome sequence test is, it is dangerous if this information is released, and since these tests are newer, security measures to protect this information is still new. Thus, increasing the likelihood of personal information being released. Also, people often find out about diseases they have that they did not expect. This can cause people to become shocked and/or depressed.

1. Facts about Alcoholism & Precautions to Take
   1. FACT: It is less than 50% likely for a child to develop alcoholism if their parent had it.
   1. FACT: Alcoholism is roughly half genetics and half hereditary.
   1. PRECAUTION: Become more cautious if you have the SNP that increases likely hood of alcoholism. Be aware when drinking or take measures if already an alcoholic.
   1. PRECUATION: If one is being cautious their self, they do not necessarily need to inform doctors, but rather family. However, if it is getting out of hand, they need to go to rehab and should immediately consult a doctor.
   1. PRECAUTION: No screenings necessary unless excessive binge drinking has occurred… should check liver and other body parts to ensure there is not any organ failure.

Works Cited

“Alcohol Facts and Statistics.” National Institute on Alcohol Abuse and Alcoholism, U.S. Department of Health and Human Services, 20 Nov. 2019, www.niaaa.nih.gov/publications/brochures-and-fact-sheets/alcohol-facts-and-statistics.

“Alcoholism.” SNPedia, www.snpedia.com/index.php/Alcoholism.

Christensen, Kurt D, and Robert C Green. “How Could Disclosing Incidental Information from Whole-Genome Sequencing Affect Patient Behavior?” Personalized Medicine, U.S. National Library of Medicine, June 2013, www.ncbi.nlm.nih.gov/pmc/articles/PMC3852635/.

Crane, Marisa. “Is Alcoholism Hereditary or Genetic?” American Addiction Centers, americanaddictioncenters.org/alcoholism-treatment/symptoms-and-signs/hereditary-or-genetic.

“Whole Genome Sequencing.” Genetics Generation, knowgenetics.org/whole-genome-sequencing/.

Genomes Blog Post

By: Emily Larking

Huntington’s Disease is an inherited neurological illness. About 30,00 people in the United States have the disease (1). It is caused by a mutation on the HD gene, that codes for huntingtin protein production which has much more repeats than normal of a certain three-basese sequence (1). This gene is located on the fourth chromosome. It causes the degeneration of nerve cells in the brain that leads to symptoms such as changes in behavior and judgement, uncontrollable movement and physical changes such as impaired ability to swallow or speak (3).

For a predictive genetic test, the price is $200-$300. There is recommended genetic counseling that can cost up to $1,500-$2,000 (4).  The most effective test is a direct-to-consumer genetic test that counts the extra repeats of the three base sequence in the Huntington gene on the fourth chromosome through a blood sample (3). The test could use a method such as the Southern Blot method. There is a very strong, almost definitive connection between the mutation in the fourth chromosome that would be tested for, and the disease.

With the direct genetic test, there is a small amount of people who have a borderline amount of repeats. Their family may be called in for genetic testing as well to get a better picture. Huntington’s can be ruled out if there are 26 or fewer repeats (3). The test can’t predict when the symptoms will start or the course of the disease (2).

There are many potential implications if the genetic testing is positive for Huntington’s Disease. There may be personal stress and possible distress to those close to the person with Huntington’s Disease. Also, Huntington’s does not have a cure. Therefore, there is no medical advantage to knowing the test results. You can only treat the symptoms as they appear. You can, however, plan for the future and factor that into any family planning decisions. The Genetic Information Non Discrimination Act (GINA) is a law that was made to stop discrimination from based on genetic information with health insurance. Although it applies to health insurance, it does not apply to life insurance so a positive test may raise prices for life insurance dramatically or may not allow for getting a policy at all. (2)

Since Huntington’s is an autosomal dominant disease, the chances of getting it if even one parent has HD will be fairly high. If both the parents have recessive alleles, the offspring will not get the disease. However, if you have two heterozygous, there’s a 75% chance of getting the disease. If one parent is heterozygous and one homozygous recessive, there’s a 50% chance. If one parent is heterozygous and one homozygous dominant, there’s a 100% chance of getting the disease. If the test is positive, the person should make a plan for the future and be prepared to address the symptoms as they come. I would recommend telling the doctor that the test was positive and ask if they have any suggestions on how to proceed.

Overall, Huntington’s Disease is an incurable disease with limited reasons to test for it. Since it is a dominant disease, there is a small chance of one developing it if it does not run through the family. Although not too complicated to test for, the consequences of a positive result outweigh the benefits in most cases.

Works Cited:

About Huntington’s Disease. (2011, November 17). Retrieved from 

https://www.genome.gov/Genetic-Disorders/Huntingtons-Disease. (1)

Genetic testing and your rights. (n.d.). Retrieved from 

https://hdsa.org/find-help/healthcare-and-future-planning/genetic-testing-and-your-rights/ . (2)

Huntington’s Disease: Hope Through Research. (2019, August 13). Retrieved from 

https://www.ninds.nih.gov/disorders/patient-caregiver-education/hope-through-research/h

untingtons-disease-hope-through#7. (3)

Goodman, L. V. (2013, January 29). Predictive Testing for Huntington’s disease. Retrieved from

 http://hddrugworks.org/dr-goodmans-blog/predictive-testing-for-huntingtons-disea. (4)

What ya Know About Obesity?

By: Kenleigh Benoit

What is Obesity?       

The term “obesity” is tossed around lightly as we do not realize just how serious the problem is. One is considered obese when their BMI (Body Mass Index) is 30 or above. The Body Mass Index is one’s weight in kilograms divided by the square of height in meters. This number indicates if a person has high body fatness. A person’s BMI is an accurate indicator of obesity because it takes into account one’s height and weight to determine if they are overweight.⁽³⁾ Obesity is a serious health problem that causes an estimated 2.8 million deaths around the world each year.⁽⁷⁾ In 2016, more than 650 million adults were considered obese and this number is only growing.⁽⁷⁾ America, being a highly developed country, is a leading country in obesity rates as two out of every three adults are considered overweight or obese.⁽³⁾ Many people are quick to place the blame on the person for obesity as they do not realize that obesity is also often inherited. Although there are many environmental factors that can affect one’s weight, there is a 64% to 84% attribute to genetics.⁽²⁾

Your genes affect your susceptibility to many diseases and traits, including obesity. Although many of them have very small effects, there are over 50 genes associated with obesity.⁽²⁾ For example, the APOA2 gene encodes the apoliprotein A-II protein. This protein affects our rates of lipid metabolism. The SNP, rs5082, occurs in the gene promoter and regulates the bodily response to an overload of saturated fat in men, leading to an increase in Body Mass Index and food intake.⁽²⁾ Another SNP, rs1421085, is located on the FTO, a fat mass and obesity gene that promotes food intake, on chromosome 16. This makes sense that these variations change the structure of the proteins as this SNP disrupts certain processes, leading to a loss of mitochondrial thermogenesis. ⁽²⁾

Why get Tested?

Obesity can cause heart disease, diabetes, and strokes, all of which are leading causes of death in the United States.⁽³⁾ You should get tested for your genetic susceptibility to obesity because there are so many diseases that could result from it. With the knowledge of your susceptibility, you can eat healthier and exercise accordingly to prevent diseases caused by obesity. If one takes the test who is not already obese, they have the option to take medication to lower blood pressure and prevent blood clots, which are two health problems related to obesity. ⁽¹⁾ The test that I would recommend that reveals your genetic risk of acquiring obesity is only $50 and uses the PCR and gel electrophoresis method as it is cost effective and gives accurate results of an individual from birth onward.⁽⁵⁾ For more accurate results, one may consider whole genome sequencing to get the most common alleles, but this test is very costly, exceeding $1325. ^{(Case Study #12)} I think it would be much more cost efficient to get the $50 test because obesity is caused by both genetics and external factors that can be controlled. Unless you have a dire problem with obesity, I would recommend taking the cheaper test that will yield similar results.

In the article on the genetic effect on obesity, author Vicky Stein claims that “In middle-aged people, those who had the highest scores weighed an average of almost 30 pounds more than those with the lowest genetic risk. The high-scoring participants were 25 times as likely to develop severe obesity as low-scoring people, and their odds of diabetes, high blood pressure, heart disease, stroke and venous thromboembolism (a dangerous blood clot condition) increased as well.”⁽⁵⁾ 30 pounds is a notable difference and knowing that you carry these risk alleles can help you create a custom health plan with your doctors to prevent obesity and disease.

What are the limitations of taking this test?

Since the risk alleles only account for about 3 kg/m2 of you Body Mass Index, one may decide to not partake in this genetic test as it is proved to not be useful. It is difficult to find the exact base risk as obesity is affected by outside factors along with genetics. Scientists have trouble finding the fine line between the two. The professors in the study, Is Genetic Testing of Value in Predicting and Treating Obesity?, claim that “The current set of identified common variants has poor specificity and poor sensitivity for predicting obesity in both cross-sectional and longitudinal studies.”⁽¹⁾ The idea that obesity is also caused by your genes is relatively new as most people thought it was solely based on what you eat and how much you exercise. Therefore, there are more than likely many variations in our DNA that scientists have not discovered a relation to obesity yet. The field is growing, so it may be influential to get the test in the future. Although genetic test for variants that causes obesity are not yet accurate, one could get a genetic test for hypothyroidism, a disease that disrupts one’s heart rate and metabolism that leads to unexplained weight gain.

What are the Ethical Concerns?

            Although obesity is a leading cause of death, it is less than a concern than say cancer or heart disease because you can work to prevent obesity regardless of your genes, which only make the process more difficult. Financially, one may have to purchase medicine and, in severe cases, surgery. This could potentially be very costly. They may also choose to partake in personalized therapy to decrease their body weight. It is also slightly more costly to purchase healthier foods. Emotionally, I believe that a person would choose to strive to live a healthy lifestyle after learning of their susceptibility to obesity.⁽¹⁾ Likewise, It may be a somewhat frightful realization as obesity leads to so many detrimental diseases and cancers that could very likely lead to death.⁽⁶⁾ If anything, a positive genetic test for obesity would make them adapt healthier habits to prevent these diseases.

There are many genetic privacy concerns that the person would have to consider. Many scientists use the results from genetic tests to discover which variants and alleles cause diseases, so they can prevent disease before it spreads. This is found through projects such as the Human Genome Project in which large amounts of people share their genetic information, but the patient could always opt to keep their results private. Other negative aspects of getting this genetic test would be one may learn that they are prone to obesity and not try to exercise to stay fit as they think it is inevitable that they will gain weight because of their genetics.

People respond to the results of genetic test differently. In a study called Parent Perspectives on Pediatric Genetic Research and Implications for Genotype-driven Research Recruitment. Some parents claimed they “wanted to help their affected child and felt that research was one way to feel like they were “doing something” in the context of uncertainty about the disease and treatment.”⁽⁶⁾ Parents all inherently want to ensure the safety of their child and if genetic test will do so, then they are in support of it. Especially with a case like obesity, learning of your child’s susceptibility will make you more aware as a parent when feeding them or helping them stay active. This is something they can prevent by taking action when the child is very young. Other parents worry of the psychological impacts on themselves and their child. They argued that “Some people cannot handle knowing what may happen to them…they can get into some anxiety by thinking this will happen down the road to them, and that’s not helping.”⁽⁶⁾ I agree with this sentiment for high risk diseases such as heart disease and cancer genes, but I think the positive results for obesity would not stress a child out. I think it will ultimately make them pay more attention to how they are living their life.

Could you be susceptible to obesity?

• Do you find yourself gaining weight at unreasonable rates?
• Are your parents or other family members considered to be obese?
• Do you see yourself as a “normal” eater and are still gaining weight?
• Do you exercise adequately and still have serious weight problems?

If you said yes to these questions, then you may have genetic mutations that make you predisposed to obesity. Does anyone in your family struggle with obesity? If so, you may be more susceptible to obesity and taking a genetic test may be needed to maintain your health. If you possess variants that make you susceptible to obesity, you should consider a genetic test for your child at birth as they have a 50% chance of acquiring that same trait. It is somewhat rare to acquire obesity through inheritance as it is often caused by environmental and lifestyle choices. It is not likely that you will get the trait from extended family members such as your aunt.

Obesity can lead to other diseases such as diabetes, depression, cancer, and heart disease. It is best to tackle the problem immediately.  If the test came back negative, they should still maintain their health even though they are not genetically susceptible to the disease. I believe it is very wise to consult your results with your doctor if you test positive as they have knowledge of how to successfully fight obesity. I would tell my doctor that I tested positive for obesity and ask what steps I needed to take to lose weight and be healthier. I would also ask about the risk of getting other diseases because of my susceptibility to obesity.

There are many environmental factors that affect obesity. If I tested positive for obesity, I would change my daily intake, exercise routine, and diet. The combination of these changes would lead to a healthier lifestyle altogether. I recommend getting screenings for diabetes, high blood pressure, high cholesterol, and heart disease if you tested positive for obesity as this puts you at risk for many illnesses. If you believe you may be susceptible to obesity, do not hesitate in taking a genetic test. Obesity is extremely harmful as it leads to so many deathly illnesses, disorders, and diseases. We must care for our bodies by living a healthy lifestyle with exercise and a fulfilling, clean diet no matter what our genes decide for us.

Resources

⁽¹⁾Bowden, D. W., Maggie C. Y., (2013). Is Genetic Testing of Value in Predicting and Treating Obesity? U.S. National Library of Medicine National Institutes of Health, 74(6): 530–533.

⁽²⁾Obesity. (2017, May 10). Retrieved November 13,2019, from https://www.snpedia.com/index.php/Obesity.

⁽³⁾Ogden, C. (2017, August 1). Overweight and Obesity Statistics. Retrieved November 13,2019, from https://www.niddk.nih.gov/health-information/health-statistics/overweight-obesity.

⁽⁴⁾Overweight & Obesity Statistics. (2013, May 17). Retreived Novemebr 13, 2019, from https://www.niddk.nih.gov/health-infomration/health-statistics/overweight-obesity.

⁽⁵⁾ Stein, V. (2019, April 18). This genetic test can predict your odds for obesity from the day you’re born. Retrieved December 2, 2019, from https://www.pbs.org/newshour/science/this-genetic-test-can-predict-your-odds-for-obesity-from-the-day-youre-born.

⁽⁶⁾Tabor, H. K., Brazg, T., Crouch, J., Namey, E. E., Fullerton, S. M., Beskow, L. M., & Wilfond, B. S. (2011). Parent Perspectives on Pediatric Genetic Research and Implications for Genotype-Driven Research Recruitment. Journal of Empirical Research on Human Research Ethics, 6(4), 41–52. doi: 10.1525/jer.2011.6.4.41.

⁽⁷⁾10 facts on obesity. (2017, October). World Health Organization. Retrieved November 13^th, 2019, from https://www.who.int/features/factfiles/obesity/en/.

The Baldness Blog

Genetic Testing for Male Pattern Baldness

By Joshua Baker

December 2nd, 2019

Men these days are judged ever increasingly more by their appearance; we need to be fit, handsome, well-dressed, and well-groomed. If we fail in any of these categories, we are instantly judged to be inferior. These are all important things to take care of, but perhaps no other physical characteristic exceeds the challenges posed by one’s own head of hair. Yes, it is our luscious locks that drive men to insanity about their appearance. But the insanity doesn’t set in until the hair follicles begin to fall out.

We are talking about male pattern baldness.

From thinning hair to a receding hair line, the condition can be devastating to a man’s self esteem and may even be linked to certain health conditions other than balding! With so much on the line, is there any way of predicting if you will develop male pattern baldness? And if so, is it even worth it? We will explore these questions and more in this blog.

WHAT IS MALE PATTERN BALDNESS?

Male pattern baldness is an inherited condition that results in the loss of significant amounts of head hair follicles. Symptoms include thinning hair, patchy bald spots, and a receding hair line¹.

According to a 2017 study by Hagenaars and colleagues, male pattern baldness affects as much as 80% of men by the time they reach 80 years old. The dramatic and unstoppable change associated with this condition is often depressing and difficult to watch for many men, not to mention its damage to their perceived social attractiveness. The same 2017 study also found 112 autosomal genes as well as 13 genes located on the X chromosome that all are associated with male pattern baldness. Several of the autosomal genes are related to hair follicle growth while the most common X chromosome gene codes for androgen reception². The genes linked with male pattern baldness naturally make sense. Because the condition concerns the loss of hair follicles, genes that cause male pattern baldness to develop must have some role in hair development. Furthermore, the fact that the androgen receptor gene is correlated with baldness raises the question that some hormonal process must be involved, which explains the sudden change that occurs.

WHY GET TESTED?

Since male pattern baldness is such a prevalent and unavoidable condition, why would one want to get genetically tested for it? If it is going to happen, then it will happen, right? For many, the emotional trauma of suddenly losing his hair is awful. But early-onset male baldness has been linked with several particularly nasty diseases, including prostate cancer and Parkinson’s disease³. As a result, getting tested early can provide relative peace-of-mind for those labeled as “low risk” and provide those labeled as “high risk” with plenty of time to prepare and start preventative measures, like prostate exams or even looking into alternatives to balding, like hair transplants.

Since there is such a massive number of genes and alleles that appear to cause male pattern baldness, it would perhaps be best to get a genome-wide sequencing test in order to detect as many of the potential variations as possible. This type of test typically runs around $1,500⁴.

For the most common alleles, it would be cheaper simply to test those specific genes. These tests cost approximately $220 for the entire gene, but for more than just one, it becomes more cost-effective to do the whole genome sequencing.

The previously mentioned 2017 study found a much higher frequency of certain variations of an X chromosome gene in men with early-onset balding than with late-onset. Therefore, it is possible to genetically test for the risk of developing early-onset male pattern baldness. In a 2012 study by Li and colleagues,Parkinson’s and early-onset male pattern baldness were found to be linked by one specific allele on chromosome 17⁵.Getting tested may be worth it for both the peace-of-mind of keeping one’s hair and not developing Parkinson’s.

THINK BEFORE YOU SPIT

A genetic test, unfortunately, is not exactly a crystal ball. Simply having the genetic variations associated with male pattern baldness is not enough to declare that a subject will become bald. Only 51.9% of the variation in the human population with respect to baldness can be explained by the genetic variants found the Hagenaars et al study². Some factors that may affect baldness outside of genes include weight, stress, chemotherapy treatment, and even simply getting older¹.

Furthermore, there may be even more variations that have not been detected yet. Research on the genetics of male pattern baldness is still relatively lacking³, so the potential for more (or even fewer) variants that cause balding is possible.

ETHICAL CONSIDERATIONS

Testing as a “high risk” candidate for balding will be terribly worrying for any man placed in such a situation. Given the possible correlations with various diseases, it would be hard not to stress over the test’s findings. Ignoring the potential for disease, even losing one’s hair, a symbol of one’s male identity, fills many with dread about future social and physical decline.

Luckily, there appear to be no major or common concerns for genetic privacy. Few companies would discriminate against an employee given his genetic propensity for balding, save those of the entertainment and modeling industry. As a result, few men should worry if getting tested for male pattern baldness might damage his prospects for future employment.

There are other downsides, though, to consider.  Given the cost and potential for inaccuracy in predicting risk of developing male pattern baldness, it may not be worth the $1,500 to sequence one’s entire genome. However, there is an added bonus. Once a genome has been sequenced, it will be available in its entirety for further analysis of other potential diseases, like risks for certain cancers. Even if the balding prediction does not hold true, having the option to also check for those awful diseases might just be worth it.

ASKING THE RIGHT QUESTIONS BEFORE THE TEST

In order to determine if genetic testing is right for you, here are some important questions to consider.

• Do you have a family history of balding, on either side?

This is important to ask because if not, then there is very little chance that the cause of any balding you might have in the future will be due to genetics.

• What will you do if you test as a high-risk individual?

If you cannot answer what you would do after being labeled as high-risk for balding, then perhaps the genetic test is not right for you. It is too expensive to simply do it for the peace-of-mind; it is best to go into the test with a plan for either treatment (if desired) or coping with balding.

• What will you do if you test as a low-risk individual?

Being labeled as a low-risk individual does not necessarily mean you are in the clear. You may still develop male pattern baldness in the future. On another note, you need to still continue to remain healthy as general health can also affect hair loss.

• Consider discussing getting the test and the results of the test with a doctor or geneticist.

Not so much a question as much as advice. If you would like to explore being tested, it would be wise to discuss your risks of balding before spending all that money on the test. Furthermore, if you have been tested and would like to consider potential treatment options and/or other genetic risks, doctors and geneticists are excellent resources to find out more about such topics.

• What are you willing to change after being identified as high-risk?

To reduce your overall chances of developing baldness even after being labeled as high-risk, it is important to try to be healthy and fit. To even further reduce risk, it may be best to consider changing your hairstyle, which can damage hair follicles, or trying to reduce stress, which can induce hair loss.

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Regardless of whether you decide it is best to get tested for male pattern baldness, it is important to maintain a healthy sense of what matters. If you are legitimately concerned about your appearance and you actively want to prevent losing your hair, then getting genetically tested is not a bad idea. But if you honestly don’t mind the prospect of balding, then that’s ok too! It is all a personal choice; no two people will have the same reasons for either decision. And regardless of that decision, above all, you need to learn to love who you are, whether that’s with a full head of hair or none at all.

Sources Cited

¹Hair loss. Mayo Clinic Web site. https://www.mayoclinic.org/diseases-conditions/hair-loss/diagnosis-treatment/drc-20372932. Updated February 12, 2019. Accessed December 2, 2019.

²Hagenaars S, Hill D, Harris S, et al.Genetic prediction of male pattern baldness. PLoS Genetics. 2017. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5308812/. Accessed December 2, 2017.

³The role of genetics in male pattern baldness. 23andMe Blog Web site. https://blog.23andme.com/23andme-research/the-role-of-genetics-in-male-pattern-baldness/. Updated March 8, 2017. December 2, 2019.

⁴The cost of sequencing a human genome. National Human Genome Research Institute Web site. https://www.genome.gov/about-genomics/fact-sheets/Sequencing-Human-Genome-cost. Updated October 30, 2019. Accessed December 2, 2019.

⁵Li R, Brockschmidt FF, Kiefer AK, et al.Six novel susceptibility Loci for early-onset androgenetic alopecia and their unexpected association with common diseases. PLoS Genetics. 2012. https://www.ncbi.nlm.nih.gov/pubmed/22693459/. Accessed December 2, 2017.

The trait I am testing for is Marfan Sydrome, an inherited genetic disease caused by a mutation in the FBN1 gene. While not very common, only occurring in around one in five thousand people (NIH), Marfan’s main symptoms are elongated limbs, worsened vision and heart issues. Only one gene is known to be the cause, and it can result from a change in any of the many alleles within the gene.

Marfan affects the production of fibrillin, a compound key to the extracelluar matrix and skeletal and muscular development¹. The condition causes the afflicted to be taller than average, along with having thin arms and legs and possible heart issues. The above average height of those with Marfan can be very beneficial for athletes, especially basketball and volleyball players. Famous atheletes with Marfan include Olympic medalist Flo Hyman and basketball player Isaiah Austin. As the mutation affects the above developments, it makes sense that those carrying it have thinner, weaker muscles due to a less strong extracelluar matrix which provides support around cells through a compound called fibrillin. Marfan leads to decreased fibrillin production, and thus less strength and elacticity in tendons and muscles. This leads to those with Marfan tending to have longer, slimmer limbs and aorta issues in the heart.

Testing for Marfan would more than likely be done to test for the likelihood of the disease in offspring. The condition is not always obvious, depending on the severity of symptoms. A SNP-ChiP is best recommended, as this test can encompass the entire gene and detect any and all SNPs which have mutated, leading to the affliction². There is no specific allele or SNP known as the cause, many different ones from FBN1 have been seen to cause Marfan³. This test can run anywhere from $200-$2000, depending on insurance and the laboratory running the test. There is a very strong connection between these mutations and the disease, as over a thousand alleles have been tied to it⁴ and if you have the mutation you will demonstrably have the disease. Getting a test done is most effective to determine risk in newborns to see if they will later develop symptoms. The risk of inheritance is fifty percent if one parent has the condition as it is autosomal dominant and those who carry the mutation are at a one hundred percent risk of developing symptoms.

Testing is not necessarily needed for this condition, but may be beneficial. Those who have any of the mutations will in many cases show symptoms and thus not need testing. Parents, however, can use testing to segregate eggs which do not carry a mutation and selectively breed children through invitro fertilization. The ethics around this are murky and can cause controversy. Adults with the condition commonly know they carry it and do not need to give up genetic information to a company just to discover they have a mutated allele they already knew about. From a scientific point of view, testing is not commonly needed. Those with symptoms should strongly consider getting tested. The main possible benefit would be that a positive would indicate possible heart issues, and further testing could be done. Getting a test done could also be beneficial for those without symptoms, as they may not visibly show it but could have Marfan and potentially develop complications. There are few ethical concerns around this kind of testing, with the only main exception being around in-vitro fertilization and selective breeding.

Family history plays a large part into having Marfan. If one parent has it, the child will have a fifty percent chance of having it as it is an autosomal dominant condition. Marfan is only inherited directly from an afflicted parent. One has a roughly one in twenty thousand chance of randomly developing it. There are no needed environmental adjustments needed if the test is positive however, as the disease is not affected by the environment. A positive or negative result from the test is only significant for a child who has not yet developed symptoms or for an adult with onlt one symptom. As Marfan is untreatable, in this case the parents could try to mitigate symptoms, but they cannot be fully treated. Adults who show as positive could also get screened for heart issues which are commonly tied to Marfan.

References

1. NIH. (2019, November 12). Marfan Syndrome. Retrieved from https://www.nhlbi.nih.gov/health-topics/marfan-syndrome#.

2. Singh et al. (2015). Single-copy gene based 50 K SNP chip for genetic studies and molecular breeding in rice. Scientific Reports, 5(1). doi: 10.1038/srep11600

3. Mayo Clinic. (n.d.). Test ID: FBN1B    FBN1 Full Gene Sequence, Varies. Retrieved from https://www.mayocliniclabs.com/test-catalog/Clinical and Interpretive/64514.

4. SNPedia. (2018, December 8). Marfan syndrome. Retrieved from https://www.snpedia.com/index.php/Marfan_syndrome.

What do we think of when we think about rare diseases? Well first of all, they’re rare: no one around me has it, my parents don’t have it, chances are, I won’t get it, nor will my children get it. Which means I don’t have to worry about getting it myself then, right?

Well let’s consider this disease: Fatal Familial Insomnia (FFI). FFI is the rarest known prion disease today – only 25 families are known to have it (2). The symptoms of the disease are initially mild – usually just an inability to sleep. As time progresses, however, there will be significant mental deterioration: dementia, problems with cognition and thought, and “dysfunction of the autonomic nervous system” (5). This impacts the human body’s ability to maintain body temperature, heart rate, and blood pressure (5). This mental deterioration continues for about a year or so until “the disease ultimately progresses to coma and death” (5).

But even as horrifying as that seems, as long as we aren’t one of the 25 families, we don’t have to worry about the disease, right? Unfortunately, it doesn’t seem completely so – in 2004, doctors studied the case of a man with the disease who was of Chinese descent – the first case of FFI ever in the Chinese population (9). This means that the disease can still occur anywhere. But ultimately, so little is known about it that scientists are struggling to find a complete explanation – and indeed, a cure – for this rare disease. Even if you don’t think you have it, getting tested for the FFI gene can provide scientists with the information they need to find the origin of the disease, and how to treat and cure it.

So what is the disease?

FFI is known as a Prion disease. These kinds of diseases occur when the PRNP gene, a gene which controls the creation of prion protein, has a mutation (5). This mutation causes the gene to create misfolded prion protein – these prion proteins are toxic and will build up in the brain, destroying important nerve cells, leading to the symptoms of the disease (5).

So far, the mutations is the genes are from SNP’s, where one small segment of the DNA is switched. D178N is a SNP for residue 178 in the PRNP gene (8). Another SNP is the M129V SNP, also in the PRNP gene (6). The last SNP is the E200K mutation, which is a common prion disease mutation (7). It’s very possible for the change in the PRNP gene, which directly creates the prion protein, to affect the prion’s shape – other prion related diseases stem from these mutations too (6).

Once someone has the disease, the disease itself is autosomal-dominant (5). That means if a parent has it, there is at least a 50% chance of the children having it too. In the case of the Canadian family mentioned before, the disease traced through the family, like the patient’s aunt (9). Since many of the patients who had the disease didn’t start showing symptoms until later in life, such as the aunt in her late 40’s (9), it is highly possible for someone who has the disease to pass it to their children.

So how can we test for it?

The best way to test for this disease would be to use traditional DNA sequencing. There is only one single gene to look at, and only at three points. All of them are SNPs, so it would be easy to know what to look for. For the three locations, the cost would be low, since there are so few of them. These mutations have a strong correlation with people who have the disease, such as D178N with a magnitude of 6.5 (8).

Unfortunately, getting the test may not be enough to prove if you have the disease or not. Because of it’s rarity, many of the mutations that can occur that will cause this disease, may not be known yet (5). It is still entirely possible to get this disease through some other mutation – take Sporadic Fatal Insomnia: this disease is the exact same as FFI, except it’s cases are completely random (4). So, even though the known SNP’s provide definitive proof of having the disease or not, the probability of having the disease is still not 0. In the end, it may be in the best interest of people, who have a family history of diseases with anything resembling the symptoms of FFI, to get tested for the disease. Even if they don’t think they have the disease, they may be some of the people with the closest connections to this disease.

What happens when I get tested?

With the rarity of the disease, most likely nothing. People who test negative for this disease will almost certainly never get it. But when they do test positive for it, it would be a horrible moment. Currently, there is no treatment for FFI; there have been so few cases, that researchers could not create a definitive treatment for it (5). Even if someone knows they have FFI, there is no definitive way to get rid of it. Once someone gets the disease, they may no longer want to keep it to themselves – the best hope to get it cured or treated would be to contact researchers for help.

If you do test positive, contact your doctor to let them know. They should know about your current condition, and if any medications you may have taken (5). If you have medication that makes any of the symptoms worse, you should stop taking them and ask your doctor if there are any alternatives (5). It is also possible to get scans done of your brain for activity, which can be especially helpful in determining where and what may be causing the symptoms (5). If you are interested in getting tested for this, ask yourself these questions: Do I have problems falling asleep? Am I experiencing forgetfulness? Do I have problems paying attention? Am I loosing weight faster than I expected? Does anyone in my family have these symptoms (5)?

Because of the lack of information about the disease, not many people know about it. However, if more people were to go and test for it, they may be able to help change that. Sonia and Eric have worked together to find a solution to the FFI disease after events in their life prompted them to do so (3). Testing for the gene doesn’t cost much, but its value is incredible for researchers. So even if it is highly unlikely for you to get this disease, just a little bit of time and money spent to get tested for this disease will help researchers save the lives of others.

Works Cited

1. Creutzfeldt-Jakob Disease Foundation, Inc. (n.d.). About CJD and Prion Disease. Retrieved from: https://cjdfoundation.org/about-cjd

2. Creutzfeldt-Jakob Disease Foundation, Inc. (n.d.). Fatal Familial Insomnia (FFI). Retrieved from: https://cjdfoundation.org/fatal-familial-insomnia-ffi

3. Creutzfeldt-Jakob Disease Foundation, Inc. (n.d.). Sonia & Eric’s Story. Retrieved from: https://cjdfoundation.org/sonia-and-erics-story

4. Medori, R., at el. (1992, February 13). Fatal Familial Insomnia, a Prion Disease with a Mutation at Codon 178 of the Prion Protein Gene. Retrieved from: https://www.nejm.org/doi/full/10.1056/NEJM199202133260704

5. National Organization for Rare Disorders. (2018). Fatal Familial Insomnia. Retrieved from: https://rarediseases.org/rare-diseases/fatal-familial-insomnia/

6. SNPedia. (2018, January 6). rs1799990. Retrieved from: https://www.snpedia.com/index.php/Rs1799990

7. SNPedia. (2018, January 6). rs28933385. Retrieved from: https://www.snpedia.com/index.php/Rs28933385

8. SNPedia. (2019, January 18). rs74315403. Retrieved from: https://www.snpedia.com/index.php/Rs74315403

9. Spacey, S.D., Pastore, M., McGillivray, B., Fleming, J., Gambetti, P., & Howard, F. (2004, January). Fatal Familial Insomnia: The First Account in a Family of Chinese Descent. Retrieved from: https://jamanetwork.com/journals/jamaneurology/fullarticle/785214

Rowan Wiley

What genes help to determine athletic performance?

The ACE and ACTN3 genes help determine what type of fibers an individual’s muscles are made up of, and whether they have more fast-twitch muscle fibers or slow-twitch muscle fibers. (2)

Fast-twitch muscle fibers can generate more power and contract more quickly and forcefully. Slow-twitch muscle fibers use oxygen more efficiently and tire more slowly. As a result, athletes who compete in strength/speed events (short-distance running) usually have more fast-twitch muscle fibers, while athletes who compete in endurance events (distance running) usually have more slow-twitch muscle fibers.

ACE

ACE instructs cells to create angiotensin-converting enzyme, a protein that converts the angiotensin hormone from angiotensin I to angiotensin II. (2)

If an individual has a variant of ACE known as ACE I/D Polymorphism, then that individual may have a higher level of angiotensin-converting enzyme. Individuals can have one of three patterns: the II pattern, the ID pattern, and the DD pattern. Individuals with the DD pattern have the highest frequency of angiotensin-converting enzymes in their muscles. These individuals tend to have more fast-twitch muscle fibers. (2)

ACTN3

ACTN3 instructs cells to create alpha-actinin-3, a protein frequently found in fast-twitch muscle fibers. (2)

If an individual has a variant of ACTN3 known as R577X, then their alpha-actinin-3 is quickly broken down, resulting in less fast-twitch muscle fibers. If an individual is homozygous for that trait (R577XX), then they have no alpha-actinin-3 whatsoever in their muscle fibers. This leads to an individual having far more slow-twitch muscle fibers than fast-twitch muscle fibers. (6)

How Prevalent are These Traits?

Frequency of ACE D allele:

66% of Asians, 59% of Nigerians, 70% of African Americans, 46-58% of Caucasians, 33-35% of Japanese, 29% of Chinese, 15% of Yanomami Indians, and 9% of Samoans have one or more ACE D alleles. (1)

Frequency of R577X allele:

>25% of Asians, <1% of Bantu Africans, ~18% of Europeans have one or more R577X alleles.

Sprint athletes: 6% XX, 50% RR, 45% RX. Control group: 18% XX, 30% RR, 52% RX. Endurance athletes: 24% XX. (9)

Gene Functions

ACE functions mainly in regulating blood pressure. It is most commonly produced by cells in the lungs, blood vessels and kidneys. (7)

It is not yet understood how variations in ACE affect athletic performance. However, there is definitely a link between blood pressure and athletic performance, so it is not surprising that ACE has an impact on athletes.

ACTN3 functions mainly in muscle fibers. It is most found in skeletal muscle. (2)

It makes sense that variations in the length of alpha-actinin-3 proteins affect athletic performance because the shorter proteins are more easily broken down, leading to a lower proportion of fast-twitch muscles.

Why get tested?

A test may be useful in order to determine what sort of muscle fibers make up an individual’s skeletal muscle and therefore what sort of athletic events they have more potential for success in.

What sort of test would be best?

A Single Gene DNA Sequencing Test that looks at either the ACE gene of the ACTN3 gene is the best option. Many tests are available that select a few key genes and examine them.

Potential options:

Atlas Sports Genetics, a company based in Colorado offers a test for $149 to determine the level of alpha-actinin-3 in an individual’s muscles. (4)

American International offers a $200 test that looks for variations in seven genes including ACTN3 that supposedly affect an individuals’ strength and endurance. (8)

How good is the evidence?

There is little evidence linking those with the ACE DD genotype to successful speed/power athletes, and the connection between the two groups is not yet understood completely. (2)

There is strong evidence showing that high-level speed/power athletes are more likely to have the R577RR genotype while high-level endurance athletes are more likely to have the R577XX genotype. However, there are plenty of examples of successful athletes in either group who do not have those genotypes, so many more factors influence strong athletic performance. (9)

Are individuals with the trait at risk?

If an individual has the ACE DD genotype then they are at risk of developing hypertension or left ventricular hypertrophy. (7)

The ACTN3 gene does not have any major risks associated with it.

Thoughts before being tested

One should consider the multitude of factors that influence someone’s athletic potential. There are so many things that affect how one performs on a physical level, much less an emotional level. As a result, one should be aware that even if the test recommends an individual for endurance sports, it doesn’t mean that that individual with necessarily be able to succeed in those events. (3)

Reasons not to get tested

Someone should not take the test if they are planning on making decisions about whether or not to compete in a certain sport, because the test in no way indicates whether or not someone will be successful, it just points out whether one has the potential to succeed.

Ethics

Taking a test to determine what variations one has of the ACE and ACTN3 genes may emotionally impact an individual if it leads that individual to believe that they either stand no chance at succeeding in a sport or stand no chance at failing in a sport. This may lead to emotional trauma. It also may lead to parents treating their children differently as a result of a child’s genotype.

Privacy concerns?

The consumer doesn’t really have to worry about companies selling their information because it doesn’t benefit the company or harm the consumer in any way. However, they may want to consider coaches treating athletes differently due to the outcome of the test, whether that is giving them more or less playing time/attention, or even a scholarship. In addition, parents may also treat their children differently or force them to play different sports. (5)

Potential downsides

Individuals may become either apathetic or overconfident as a result of test results, and may even give up on an activity due to their genetic variations.

How do people respond to the test?

There are not any studies done on how people respond to the knowledge because it isn’t generally in the interest of the companies to see how parents react to the results.

Pre-Test Considerations

Runs in the family?

The vast majority of the tests that are currently offered look at the level of alpha-actinin-3 in an individual rather than the individual’s genotype, and variation in the ACTN3 gene only accounts for a small percentage of variation in muscle composition, so one family member’s will not necessarily predict the results of another family member’s test. (3)

How to respond to the test

An individual shouldn’t decide what sports they or their children play based on the results of the test, but it may be worth trying new things that the test claims one might be good at. 

Tell a doctor?

There is no reason to tell your doctor about your results if you take a test based on the ACTN3 gene because variations in the gene don’t lead to any risks. However, one should tell a doctor if a test reveals that you are ACE DD because of the heightened risks of hypertension and left ventricular hypertrophy.

Further actions

No screenings are necessary because the test does not reveal any health conditions and should not lead one to drastically alter their lifestyle unless one has the ACE DD variation in which case one should have their blood pressure monitored.

Sources

1. Al-Hinai et al. “Genotypes and Allele Frequency of Angiotensin-Converting Enzyme (ACE) Insertion/Deletion Polymorphism among Omanis.” U.S. National Library of Medicine – National Center for Biotechnology Information, Apr. 2002, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3174717/
2. “Is Athletic Performance Determined by Genetics?” U.S. National Library of Medicine – Genetics Home Reference, https://ghr.nlm.nih.gov/primer/traits/athleticperformance
3. MacArthur, Daniel. “The ACTN3 Sports Gene Test: What Can It Really Tell You?” Wired, 30 Nov. 2008, https://www.wired.com/2008/11/the-actn3-sports-gene-test-what-can-it-really-tell-you/
4. Macur, Juliet. “Born to Run? Little Ones Get Test for Sports Gene.” The New York Times, 29 Nov. 2008, https://www.nytimes.com/2008/11/30/sports/30genetics.html
5. Mannino, Barbara. “Testing Kids for a Sports Gene: Would You Do It?” FOX Business, 29 Jun. 2011, https://www.foxbusiness.com/features/testing-kids-for-a-sports-gene-would-you-do-it
6. Pickering, Craig, and Kiely, John. “ACTN3: More Than Just a Gene for Speed.” U.S. National Library of Medicine – National Center for Biotechnology Information, 18 Dec. 2017, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5741991/
7. Rana et “al. “Association of DD Genotype of Angiotensin-Converting Enzyme Gene (I/D) Polymorphism with Hypertension among a North Indian Population.” U.S. National Library of Medicine – National Center for Biotechnology Information, 2 Aug. 2017, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5752652/
8. Stein, Rob. “Genetic Testing for Sports Genes Courts Controversy.” The Washington Post, 18 May. 2011, https://www.washingtonpost.com/national/genetic-testing-for-sports-genes-courts-controversy/2011/05/09/AFkTuV6G_story.html
9. Yang et al. “ACTN3 Genotype is Associated with Human Elite Athletic Performance.” U.S. National Library of Medicine – National Center for Biotechnology Information, 3 Jul. 2003, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1180686/

Images

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https://ghr.nlm.nih.gov/gene/ACE

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