The numbers are frightening: 1 in 4 Ashkenazi Jews is a carrier for at least one genetic disease. The genetic mutations responsible for these diseases have been passed on from a very small original population — our ancestors who migrated from the Middle East to Eastern Europe around 70 C.E. This is called the founder’s effect. Because Jews tended to marry among themselves, the gene pool remained homogenous and the mutations continued to be inherited.
These mutations are mostly recessive, meaning that mutations must be present in both copies (alleles) of the gene for the associated condition to be expressed. When both parents carry a given mutation, each child of theirs has a 25% of developing the associated disease. This is why couples among whom at least one partner has one or more Ashkenazi Jewish grandparents are urged to undergo genetic screening before conceiving children.
Most labs offer panels that screen for the 19 most common disease carriers, and many insurance companies cover the cost of testing. Some providers offer saliva screenings, though blood tests are more common, and carriers for some diseases — like Tay-Sachs — can only be reliably detected using blood samples.
The Forward Staff has put together a guide to the 19 most common heritable “Ashkenazi Jewish diseases” along with information on symptoms, causes and carrier and detection frequency for each. We’ve also listed support groups in the United States.
Not included on this list are some mutations that are not typically screened for before pregnancy, such as those of the BRCA genes. Because each individual might be at risk for different mutations due to familial risk factors, personal genetic counseling is recommended in conjunction with screening.
Data on the estimated carrier rate are courtesy of the Yeshiva University Program for Jewish Genetic Health in New York. Data on the disease incidence are taken from the the paper ‘Carrier testing for Ashkenazi Jewish disorders in the prenatal setting: navigating the genetic maze’ published in the American Journal of Obstetrics and Gynecology in February 2014.
Dr. Adele Schneider, the medical director of the Einstein Victor Center for the Prevention of Jewish Genetic Diseases in Philadelphia, Pennsylvania, has contributed to this section.