Expansion and de novo occurrence of Y chromosome microdeletions occurring via natural vertical transmission in northeastern China.

ABSTRACT

OBJECTIVE: To determine characteristics of classical and partial deletions of the Y chromosome azoospermia factor (AZF) region transmitted from father to son by natural fertilization. METHODS: Patients from northeastern China with primary male infertility (n = 10) and their fathers were investigated. Healthy fertile men and women were recruited as positive and negative controls, respectively. The Y chromosome microdeletions were detected by polymerase chain reaction. Serum concentrations of reproductive hormones were determined by electrochemiluminescence immunoassay and enzyme-linked immunosorbent assay. RESULTS: Expansions of microdeletions were observed in seven father­son pairs; de novo microdeletions were found in the remaining three father­son pairs. The Y chromosome microdeletions were larger in sons than in their fathers. Patients with infertility had significantly higher levels of follicle stimulating hormone and lower levels of inhibin B than fertile men. CONCLUSIONS: The Y chromosome microdeletions were transmitted from father to son via natural transmission. These microdeletions may expand during transmission or arise de novo, possibly resulting in reduced fertility.