Prenatal diagnosis of mos46,X,del(Y)(q11.2)/45,X by cytogenetic and molecular studies with multiplex STR analysis

OBJECTIVES: To present the prenatal diagnosis of a fetus of mos46,X,del(Y)(q11.2)/45,X by cytogenetic and molecular analysis. CASE AND METHODS: A 35-year-old pregnant woman came to our hospital for amniocentesis, and fetal chromosomal aberrations with mos46,X, + mar/45,X were found. Fluorescence in situ hybridization revealed the existence of a Y centromere on the marker chromosome. Analysis with six pairs of short tandem repeat markers showed that the genomic DNA extracted from the uncultured amniotic fluid cells contained a deletion of Yq11.1-Yq11.2. Spermatogenesis loci of the Y chromosome were studied using four sets of multiplex PCR. The proximal two markers DYS271 and KALY were present and the other 16 distal markers were deleted. No deletion was noted in the Y chromosome of the father. RESULTS: Cytogenetic and molecular analyses revealed deletions of AZFb, d, and c regions on Yq11.2-Yqter in the fetal Y chromosome. Postmortem examination of the fetus showed a grossly normal male fetus with normal external genitalia and testes. CONCLUSION: The present report demonstrates that molecular analysis using polymorphic microsatellite markers and multiplex PCR is a useful complement to cytogenetic methods for the identification and the characterization of Y-chromosomal deletions.