What will your children and grandchildren do when they start planning their families? For anyone with a Jewish background, the answer to this question should always include genetic testing, to help avoid devastating disorders like Tay-Sachs disease. But the technologies that allow us to detect these carrier mutations are changing rapidly, often improving our ability to use and interpret results and driving down the cost of the tests.
You or your parents may have participated in a community screening for Tay-Sachs in the early 1970s. Other young couples might have benefited more recently from the Center for Jewish Genetics education and screening programs, which presently screen for 18 disorders of increased frequency in people of Ashkenazi descent. In the future—and not so far in the future at that—whole genome sequencing could be available to and affordable for everyone.
Whole genome sequencing, once the stuff of science fiction, exists today, though mainly on a research basis, at costs prohibitive for most of the general public. But that doesn't make its benefits out of reach. Only three percent of an individual's DNA sequence carries functionally important instructions responsible for building and running our bodies. This portion is called the exome, comprising approximately 20,000 genes. Exome sequencing is also available now, and is much more cost-effective than analyzing an entire genome.
Exome sequencing is not yet ready to replace our current practices. Unlike the carrier testing we offer at the Center, it is a diagnostic test, used when an individual has clinical features or symptoms suggestive of a genetic disorder, but no specific diagnosis has been identified. Currently, many families reach a point with an undiagnosed child where no other testing is available; now exome sequencing may offer that next key step, and hopefully some answers for possible treatments and management of care. And while exome sequencing is not cheap-a patient can pay $1,000 after insurance at certain labs, though the test is billed at $5,000—ordering a handful of individual genetic tests can cost significantly more. Soon doctors may be able to use exome sequencing earlier in the diagnostic process, saving everyone time and money.
What does this mean for the rest of us? As technology advances, so too does knowledge and awareness in the field of genetics, which can positively affect medical outcomes. For instance, geneticists used to clump Sephardic Jews into one genetic category, like Ashkenazi Jews, who are genetically very similar regardless of country of origin. Thanks to DNA sequencing and analysis, we have since learned that Sephardic Jews' risk factors for different disorders vary greatly based on ancestry; an individual of Iraqi descent would be tested for different conditions than an individual of Greek or Moroccan descent. Naturally this has implications for diagnosis and treatment, and it is thanks to technology that we can improve our understanding of these processes.
If you, your children, or your grandchildren want to plan families now, not years in the future, the Center for Jewish Genetics (www.jewishgenetics.org) offers a highly subsidized carrier screening program for $180 per person. We at the Center see the results of technological advances every day: in the decade since we began screening, we have expanded our testing panel from three to 18 diseases, all while keeping the costs to participants well below the price point for these tests in commercial labs. In ten years, we fully expect the testing landscape to have changed all over again, with greater benefits to more people than ever, and we can only imagine the advances that are to come.
The Center for Jewish Genetics is a collaborative effort of the Jewish Federation of Metropolitan Chicago and the Ann & Robert H. Lurie Children's Hospital of Chicago.
Michelle Gilats, MS, CGC, is a genetic counselor at Ann & Robert H. Lurie Children's Hospital of Chicago. Esther Bergdahl is senior program associate at the Center for Jewish Genetics, the new name for the Chicago Center for Jewish Genetic Disorders.