Healthy Living

DNA: When Ancestry Matters

DNA: When Ancestry Matters

In recent years, it has become increasingly popular to undergo genetic testing that can tell you more about your ancestry. People all around the world want to know more about where they came from. However, new insights about your ancestry can leave you with many questions about what the results mean, especially when you’re planning to start a family.

Ultimately, the fact remains that DNA can play a huge role in health outcomes throughout the lifespan. This includes inherited genetic disorders that you are born with, genetic mutations that put you at risk for developing a particular condition later in life, and the potential to pass on any of these genetic disorders to your unborn child.  So, when does ancestry matter beyond the family tree?

Inherited Genetic Disorders

You may have inherited a particular genetic disorder from your parents. Many of these conditions are passed down through generations, and while some have the same incidence around the world, others occur more often within certain ethnic groups. For example, sickle cell disease (SCD), which causes severe anemia, is commonly found among people of African or Hispanic ancestry.

As with SCD and other recessive inherited genetic disorders, you do not necessarily need to have the disease in order to pass it on to your children. If you are a carrier (you only received a gene for the disease from one of your parents), you will not develop the condition. However if both you and your partner are carriers of a recessive trait for a disease, your child has a chance of receiving one disease gene from each of you and being born with the condition. A genetic counselor can help you to better identify what diseases you and your partner may be at risk for passing on based on your ancestry and family history. 

Genetic Predispositions

There are certain inherited genetic mutations that do not necessarily cause a particular disease, but rather increase the likelihood that someone with that mutation will develop the disorder down the road. The BRCA1 and BRCA2 gene mutations are a common example of this. These mutations have been found to correlate with an increased risk for certain cancers in women, like breast cancer and ovarian cancer. In these cases, individuals found to have a BRCA gene mutation are much more likely than the general population to develop these conditions. It’s important to know what genetic predispositions you have inherited and understand your risk of passing them on to your child in order to place an emphasis on prevention and screening. As with inherited genetic disorders, these genetic mutations and predispositions are also more prevalent within a particular ethnic group. For instance, the aforementioned BRCA gene mutations previously discussed are often found in higher rates among women of Ashkenazi Jewish ancestry. 

Genetic Carrier Screening

DNA testing can play a huge role in understanding the risk that your child will be born with a genetic disorder. If you or your partner have a family history of a particular genetic disorder somewhere in your ancestry, your doctor may recommend that you both undergo genetic carrier screening before becoming pregnant to better understand the risks.

It’s also important to note that this test does not guarantee that your child will be born will a particular inherited genetic disorder. What it does is give you a better idea of the risks. An increased risk does not mean that you may not be able to have children with your partner, but that you might explore other options like preimplantation genetic testing with in vitro fertilization or the use of a sperm or egg donor. Your genetic counselor will be able to guide you through the options and help you make a decision.

Finding a Genetic Counselor

If you have questions about your family’s health history, it may be a good idea to find a qualified genetic counselor in your area. They will be able to formulate important discussion questions, point you in the right direction for any necessary testing, explain test results, and help you to determine your options after you receive the results.

SOURCES:

  1. https://www.gaucherdisease.org/blog/5-common-ashkenazi-genetic-diseases/
  2. https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet
  3. https://www.nsgc.org/page/find-a-genetic-counselor
  4. https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentID=P02142&ContentTypeID=90
  5. http://www.who.int/genomics/public/geneticdiseases/en/index2.html
  6. https://www.bmc.org/genetic-services/ethnic-based
  7. https://ghr.nlm.nih.gov/primer/inheritance/runsinfamily
  8. https://ghr.nlm.nih.gov/condition/tay-sachs-disease#statistics
  9. https://ghr.nlm.nih.gov/condition/sickle-cell-disease#synonyms
  10. https://www.nhlbi.nih.gov/health-topics/sickle-cell-disease

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