Mosaic ring Y chromosome in two normal healthy men with azoospermia

To better define by molecular and cytogenetic techniques ring Y chromosomes detected in 2 infertile men. Case report. Molecular genetics/cytogenetics unit in a university hospital. Two infertile men with azoospermia, presenting a normal male phenotype with complete masculinization. Karyotype and genetic counseling. Metaphases were studied by standard G- and Q-banding; fluorescent in situ hybridization and PCR were performed to analyze specific Y chromosome regions. Chromosomal analysis detected a mosaicism with a Y chromosome ring cell line in 92% (patient 1) and 95% (patient 2) of the metaphases, coexisting with a 45,X cell line in the remaining metaphases. In patient 1, PCR analysis showed the presence of AZFa region and a partial deletion of AZFb region; AZFc region was deleted. In patient 2 all three AZF regions were deleted. A 45,X/46,X,r(Y) mosaicism can be detected not only in patients with Ullrich-Turner syndrome and in patients with various degrees of genital ambiguity but also in men presenting a normal phenotype. Their azoospermia can be explained by partial or total deletion of AZF regions.