RESUMEN
Xp/Yq translocations are rare chromosomal rearrangements, and the phe-notype of male carriers varies according to the segment of the Xp region that is deleted. In this case report, we describe a der(X)t(X;Y)(p22.31;q11.22) translocation, detected by conventional cytogenetic analysis, in a male fetus at a gestational age of 16 weeks. Chromosomal analysis of parental blood confirmed that this chromosomal aberration had been maternally inherited. Array comparative genomic hybridization (CGH) analysis of fetal blood further indicated a nullisomy of Xp22.31-pter and a breakpoint between the STS and KAL1 genes. The STS, NLGN4, ARSE, CSF2RA, and SHOX genes are present in the region that was deleted, and are known to be related to conditions such as X-linked ichthyosis, chondrodysplasia punctata, mental retardation, and facial dysmorphism in humans. Prenatal ultrasonographic findings and autopsy results were consistent with Xp22.31-pter deletion phenotypes. Genetic counseling was provided for the mother. The observations from this case study indicate that advanced molecular techniques can provide a more precise prenatal diagnosis of chromosomal anomalies than conventional cytogenetics can.