Dicentric Y chromosome without evidence of mosaicism in an azoospermic male.

A phenotypically male of dicentric Y chromosome with no evidence of sex chromosomal mosaicism is reported. Staining of fluorescence in situ hybridization using Y chromosome centromere-specific DNA probe showed the presence of two bright fluorescent spots in Y chromosome. Testicular histology revealed maturation arrest at the stage of primary spermatocyte. It is suggested that structural anomaly of the Y chromosome is related to the disturbance of spermatogenesis.