Heterozygote screening for Tay-Sachs disease: past successes and future challenges.

Tay-Sachs disease (TSD) is an autosomal recessive, neurodegenerative disorder caused by a deficiency of beta-hexosaminidase A activity. Mass screening for TSD heterozygotes has been routine in the Ashkenazi Jewish population since the early 1970s. Recent advances in the molecular genetics and epidemiology of TSD require a reevaluation of heterozygote screening practices. The use of DNA-based analyses for a panel of common mutations detects about 98% of TSD mutations found in the Ashkenazi Jews and about 50% of TSD mutations found in the general non-Jewish population; enzyme-based analysis has nearly 100% sensitivity for all populations. We recommend 1) that members of several ethnic groups and persons with a family history consistent with TSD be offered testing for TSD heterozygosity and 2) that assays of enzyme activity be used as the primary screening tool, with mutation analysis used as an adjunct tool in certain cases.