The period leading to, and following, birth of a child is also a time when you might be curious about your ancestry. You might want to have your DNA tested by a genealogy company, such as Family Tree DNA, 23andMe, Ancestry DNA, Geno 2.0 , or some of the others that are out there. It is quick and painless. You mail a saliva sample, pay somewhere around $100-200, and voilà. You learn all kinds of cool things about your genetic heritage, that you have roots in this part of the world, or somewhere else, and some people are very surprised. You thought you were mostly West African, but there’s a Native American tribe accounting for a big fraction of your heritage. Your Jewish great grandparents all arrived at Ellis Island, New York from Eastern Europe around 1900, but your test says that you’re 15 percent from East Asia –maybe because of the Mongol Empire invading Europe in the 13th Century– and that your matriarchal line is mostly Italian. Or, you learn that your Catholic lineage in South America has some genetic sequences common among Jews, suggesting that some ancestor converted to Christianity to escape the Spanish Inquisition.
All of this can be fascinating, but there’s also a health dimension to the tests. For a while, 23andMe has been giving customers in Canada and the United Kingdom test results relevant to certain diseases, along with the genealogy, but now that will happen in the United States as well. In Early April of this year, the US Food and Drug Administration announced that it would allow 23andMe to tell customers whether their tests show genetic markers for any of ten different diseases.
For several conditions, mostly conditions that show symptoms during the perinatal period, infancy, and early childhood, information on whether you carry risk will be provided automatically, if you take the 23andMe Ancestry and Health test for $199. On the other hand, risk for two common neurodegenerative conditions that typically strike much later in life will be provided, only to customers who indicate that they want those results.
Conditions for which 23andMe will report risk automatically include the following:
- Celiac disease: Also called celiac sprue, this can show up in adults, but often begins toward the end of the first year of life. It is managed easily with a special diet, so it can be very helpful to know if a newborn, or the family, carries a genetic risk. However, genetic factors work together with outside factors, some of which are not known, so having risk genes is not a guarantee that one has the disease.
- Type I Gaucher disease: This affects mostly Ashkenazi Jews and shows up as problems in the liver, muscles, bone, and blood clotting. It is inherited with autosomal recessive genetics, meaning that both parents must be carriers for a child to have the condition.
- Factor XI deficiency (Hemophilia C, Rosenthal syndrome): A blood clotting disorder that also affects mostly Ashkenazi Jews. As with the better known types of hemophilia (hemophilia A and B), inheritance is recessive, but in this case the recessive inheritance also autosomal, not carried on the X chromosome, so boys and girls are affected equally. In girls, it may show up the first time when menstruation begins. In boys, the first clue may be heavy bleeding on circumcision, so it’s a good thing to know early for someone with a new child.
- Glucose 6-Phosphate Dehydrogenase (G6PD) deficiency: A problem with red blood cells that typically affect people with heritage in tropical and subtropical regions where malaria has been common in the past few centuries. This tends to be people of African, Asian, and Mediterranean descent. It shows up as hemolytic anemia (anemia resulting from destruction of red blood cells), provoked by a variety of drugs and foods. Inheritance is X-linked recessive, which means that it affects mostly boys.
- Alpha-1 anti-trypsin deficiency (AATD): This affects Caucasians more than other groups. In neonates, it presents itself as hepatitis and is the most common reason why a child would need a liver transplant. In adults, AATD causes liver disease and emphysema much earlier than it would be expected (in the forties for nonsmokers and thirties for smokers).