title: First-trimester prenatal diagnosis of Tay-Sachs disease.
abstract: The prenatal diagnosis of Tay-Sachs disease was made in two at-risk fetuses by the analysis of chorionic villi obtained at 9 and 11 menstrual weeks, respectively. The diagnoses were based on the absence of beta-hexosaminidase A activity as determined by: (1) specific enzyme assays, (2) anion-exchange chromatography, and (3) cellulose acetate gel electrophoresis. The enzymatic diagnoses were confirmed on fetal tissue as well as by ultrastructural demonstration of the first-trimester fetal neuropathology. Optimal assay conditions for beta-hexosaminidase A in chorionic villi were established for the prenatal diagnosis of Tay-Sachs disease. Importantly, it was noted that a small amount of decidua or maternal blood could lead to misdiagnosis. Thus, extreme care must be taken in the preparation of chorionic villi for Tay-Sachs as well as other prenatal metabolic diagnoses.
mesh_terms: D001921:Brain / Q000648:ultrastructure; D002824:Chorionic Villi / Q000201:enzymology; D002852:Chromatography, Ion Exchange; D004588:Electrophoresis, Cellulose Acetate; D005260:Female; D005333:Fetus / Q000648:ultrastructure; D006596:Hexosaminidases / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis; D013661:Tay-Sachs Disease / Q000175:diagnosis*; D001619:beta-N-Acetylhexosaminidases
chemical_list: D006596:Hexosaminidases; D001619:beta-N-Acetylhexosaminidases