Mosaic ring Y chromosome in two normal healthy men with azoospermia.

Objective: To better define by molecular and cytogenetic techniques ring Y chromosomes detected in 2 infertile men.

Design: Case report.

Setting: Molecular genetics/cytogenetics unit in a university hospital.

Patient(s): Two infertile men with azoospermia, presenting a normal male phenotype with complete masculinization.

Intervention(s): Karyotype and genetic counseling.

Main Outcome Measure(s): Metaphases were studied by standard G- and Q-banding; fluorescent in situ hybridization and PCR were performed to analyze specific Y chromosome regions.

Result(s): 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.

Conclusion(s): 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.