A number of devastating genetic diseases are slowly disappearing because of genetic testing, according to a report by Associated Press. Tay-Sachs disease, a neurological illness that cropped up among Ashkenazi, or Eastern European Jews, has almost disappeared. Affected children lack a key enzyme and this causes them to decline physically and mentally until death at about the age of 4. But in the last decade, there have only been about a dozen cases of Tay-Sachs each year in the US.

“Now, more women are being tested as part of routine prenatal care, [says AP] and many end pregnancies when diseases are found. One study in California found that prenatal screening reduced by half the number of babies born with the severest form of cystic fibrosis because many parents chose abortion.”

In California, for instance, Kaiser Permanente, a health care group, offers pre-natal screening. From 2006 to 2008, 87 couples were identified as carriers of cystic fibrosis mutations and 23 foetuses were found to have the disease – 20 of them were aborted.  

Another fatal disease associated with Ashkenazi Jews is familial dysautonomia, which affects children psychologically, mentally and physically. It causes faulty nerve development, floppy muscles, digestive and other problems, and kills many by young adulthood. Because of screening only one child is born with the condition a year in the US and geneticists think that the disease may cease to exist.

But is this an unreserved good, asked Columbia University medical historian Barron Lerner in a thoughtful article in the New England Journal of Medicine last year. Is it tantamount to eugenics, with all its horrific baggage? Will the disappearance of the disease make fund-raising for research into alleviating it harder? ''If a society is so willing to screen aggressively to find these genes and then to potentially to have to abort the fetuses, what does that say about the value of the lives of those people living with the diseases?'' he asks. ~ New England Journal of Medicine, Oct 22, 2009; AP, Feb 17