Of the last 100 people tested at Sinai, Dr. Cash says, three turned up as car- riers, bearing out the statistics. The chances of a Jewish Tay-Sachs child being born is 100 times greater than in the general population or among Sephardi Jews. But the experts say Robin Gold and Dr. Ralph Cash. these are statistical probabilities — just numbers. In reality, the genetic one-in-3600 chance of a Tay-Sachs birth can't be totally predicted by numbers. Sinai's Robin Gold says it really is a genetic crapshoot. "We all have five or six recessive genes. This one we know about. With Tay-Sachs, out of four pregnancies, one should have the disease. In reali- ty:' she says, "you could conceive four times and have four Tay-Sachs babies — that 25 percent could come up each time. The normal baby could come on the fifth try. Or you could have a nor- mal pregnancy 75 percent of the time." The origins of Tay-Sachs are still noticed a peculiar, cherry-colored red spot on the retinas of affected infants' eyes. Seven years later, New York neurologist Dr. Bernard Sachs was the first to describe the changes in brain cells caused by the disease, as well as notice it was a familial condi- tion with ties to the Ashkenazi Jewish community. In the 1940s, a German scientist described the abnormal accumulation of nerve killers (gangliocides) in the brain tissue of afflicted children. It wasn't until 1968 that researchers isolated the culprit: the lack of the en- zyme hex-A. Tay-Sachs is not only deadly but insidious. An affected child is born seemingly normal and happy parents watch the infant progress through the first five or six months of life. Then changes start to appear as develop- ment slows and the baby begins to regress. A baby may start having trouble sitting up, or grasping a toy or bottle since eyesight and muscle function are beginning to deteriorate. Tay-Sachs infants also exhibit a hypersensitivity to sound or an exag- gerated "startle" reflex. They'll jump or shudder excessively at loud noises, says Dr. Cash. As the first year progresses, Dr. Cash says the stricken infant's Bob McKeown eyesight worsens and involuntary disease married and conceived a Tay- muslce seizures set in. Bit .bfbit", the disease robs the child of its senses and Sachs baby. The trait, which is most common muscle responses. The child is no to Eastern European Jews, likely longer able to turn over, to sit, to started in the Jewish population, says reach out, to crawl, even to swallow. Eventually, the child becomes Dr. Mark I. Evans, director of repro- blind, deaf, mentally retarded, unable ductive genetics at Hutzel Hospital. Evans says the disease remained in to move and totaly unresponsive to the defined population for a long time the outside world. They usually sink into a coma, because of breeding patterns — peo- ple finding mates only within that says Dr. Cash, as their bodies are group. "I don't think there's any ques- wracked by uncontrollable seizures tion that inbreeding in the Pale of and repeated infections. By the time Settlement caused this trait to be so the disease runs its course, the baby's head has become enlarged due to the prevalent;' says Dr. Cash. Medical science has know for on- accumulation of fat in the brain ly the last 20 years what actually tissue. Even with the best of care, a causes Tay-Sachs. The first real clue Tay-Sachs child doesn't live past the came in 1881, when a British op- age of five. The double tragedy in all this thamologist named Dr. Warren Tay a genetic mystery. "No one knows how Tay-Sachs started;' says Dr. Cash. "Possibly some time in the Middle Ages a genetic mutation may have oc- curred — and they do occur." The mutation could have been passed on until two people who carried the Free Tay-Sachs screenings at five locations will' be held in suburban Detroit on Jan. 15. THE DETROIT JEWISH NEWS 23