RAPID PRENATAL-DIAGNOSIS OF 14 CASES OF TRIPLOIDY USING FISH WITH MULTIPLE PROBES

Fluorescence in situ hybridization (FISH) of chromosome-specific probe s to interphase nuclei can rapidly identify aneuploidies in uncultured amniotic fluid cells. Using DNA probe sets specific for chromosomes 1 3, 18, 21, X, and Y, we have identified 14 fetuses where the hybridiza tion pattern was consistent with a triploid chromosome constitution. I n each case, the identification of fetal abnormalities by ultrasound e xamination initiated a request for rapid determination of ploidy statu s via prenatal FISH analysis of uncultured amniocytes. FISH produced a three-signal pattern for the three autosomes in combination with sign als indicating an XXX or XXY sex chromosome complement. This hybridiza tion pattern was interpreted to be consistent with triploidy. Results were reported to the physician within 2 days of amniocentesis and subs equently confirmed by cytogenetics. These cases demonstrate the utilit y of FISH for rapid prenatal identification of triploidy, particularly when fetal abnormalities are seen with ultrasonographic examination.