PRENATAL IDENTIFICATION OF I(YP) BY MOLECULAR CYTOGENETIC ANALYSIS

An i(Yp) is a rare marker chromosome. We present a case of de novo 46, X,i(Yp) detected prenatally in an amniotic fluid specimen. Fluorescenc e in situ hybridization (FISH) studies using a panel of Y-specific bio tinylated DNA probes identified the marker chromosome as i(Yp). Compar ative genomic hybridization (CGH) studies further confirmed the diagno sis. Upon pregnancy termination, external examination of the fetus rev ealed a generally well-developed male fetus with slight facial dysmorp hism and prominent rocker-bottom feet. The molecular cytogenetic data in this case proved very useful in genetic counselling and served as a good example illustrating the important role of molecular techniques for accurate identification of marker chromosomes.