EVALUATION OF X, Y, 18, AND 13 21 ALPHA-SATELLITE DNA PROBES FOR INTERPHASE CYTOGENETIC ANALYSIS OF UNCULTURED AMNIOCYTES BY FLUORESCENCE IN-SITU HYBRIDIZATION/

The major aneuploidies diagnosed prenatally involve the autosomes 13, 18, and 21, and sex chromosomes. Fluorescence in situ hybridization (F ISH) allows rapid analysis of chromosome copy number in interphase cel ls. This prospective study evaluated the use of four commercially avai lable centromeric DNA probes (DXZ1, DYZ1, D18Z1, and D13Z1/D21Z1) for direct analysis of uncultured amniocytes. One hundred and sixteen amni otic fluid samples were analysed by FISH and standard cytogenetics. Th is evaluation demonstrated that FISH with, X, Y, and 18 alpha satellit e DNA probes could accurately and rapidly detect aneuploidies involvin g these chromosomes and could be used in any prenatal clinical laborat ory. In contrast, the 13/21 alpha satellite DNA probe hybridizing both chromosomes 13 and 21 was unreliable for prenatal diagnosis in uncult ured amniocytes.