Last month, I received an email from a third cousin on my mother’s side of the family who lives in the United States. While we have never met, we have corresponded for a few years and have exchanged genealogical information on our respective branches. We also see each other on Facebook, so I was aware she had married in December. She began by telling me she and her new husband are planning to have children and, because some of her family members are carriers of Tay-Sachs disease and Joubert syndrome, the couple decided to undergo genetic testing.
Tay-Sachs disease is one of the genetic disorders that affect Ashkenazi Jews at a rate higher than the general population. There is no known cure for this neurological disease and children born with it generally do not live beyond the age of four. If two carriers of the disease have a child, there is a 25 per cent chance of the child being affected; a 50 per cent chance of the child being a carrier; and a 25 per cent chance of the child not being affected or a carrier.
Since there is no cure, many young Jewish couples undergo the testing to see if they are carriers. If the testing establishes they are both carriers, the couple is given the tools to make an educated decision whether or not to start a family, knowing the possible consequences.
In my cousin’s case, it turned out that neither she nor her husband were carriers of either of the two diseases. Interestingly, in this case, the testing was done under the watchful eye of her aunt, who just happens to be an expert in genetic diseases, and who works in that field in Philadelphia. The aunt decided to test for more than the usual Ashkenazi-affected diseases, and found that my cousin was a carrier of something known as familial Mediterranean fever (FMF).
FMF, which is quite treatable and is very rare among Ashkenazi Jews, is more prevalent among Sephardi Jews. Not being aware of any Sephardic roots, she wrote to me, as the family historian, to tell me we may have Sephardic background somewhere in our family. Of course, since it is her father who is a member of our family, and the gene may have been passed down from her mother, our branch may not be affected at all. She did suggest, though, that I might wish to pass this information on to other cousins so they could decide to have expanded genetic testing, or at least be aware there is a slight possibility some of us might be carriers.
Combining genealogy and genetics is not a new concept. One of the world’s most prominent Jewish genealogists, and probably the best known in Canada, is Stanley Diamond, president of the Jewish Genealogical Society of Montreal, and founder of Jewish Records Indexing – Poland. Diamond began his genealogical research because, in 1977, he discovered that he, his three siblings and nine of their combined 13 children were carriers of beta thalessemia trait.
Several years after making this discovery, Diamond found out his family had come from the town of Ostrow Mazowiecka, Poland, so he went to great lengths to obtain records from the town to determine if there were other people descended from a common ancestor who might have also been carriers of the trait. His efforts led to the establishment of JRI-Poland, which is the most important resource for those researching their Jewish roots in Poland.
“How I Have Traced the Beta Thalassemia Trait,” a fascinating article written by Diamond for the winter 2006 issue of Avotaynu magazine, can be read at www.diamondgen.org/trace.pdf.
Many people are now doing genetic or medical genealogy to identify potential health issues and life expectancy in their families. There are software programs designed to capture the information, and online forms available to download to use when interviewing family members about their medical histories. Since about 30 per cent of known diseases have genetic links, compiling a medical history of one’s family that covers several generations can be interesting, informative and potentially life-saving.
I know that, in my own family, there is a higher than average incidence of Crohn’s disease and colitis. Perhaps my next project will be an attempt to figure out where that came from and to try to predict how it will affect future generations.