Molecular analysis of the Y chromosome AZFc region in Japanese infertile males with spermatogenic defects.

Cytogenetic and molecular studies of azoospermic and oligozoospermic males have suggested the presence of azoospermia factors (AZF) in the human Y chromosome. Deletion in three Y chromosomal regions--AZFa, AZFb and AZFc--has been reported to disrupt spermatogenesis and cause infertility. Several candidate genes responsible for spermatogenesis have been identified in these regions and some of them are thought to be functional in human spermatogenesis. Here we report on clinical and molecular studies of Y chromosome micro-deletions in Japanese. In these studies the data from 157 infertile Japanese men with azoospermia and oligozoospermia was analyzed and divided into 5 categories based on spermatozoa count. Sixteen sets of primers were used for polymerase chain reaction (PCR) to amplify sequence tagged site markers. One common deletion in the AZFc region was identified in infertile men. On the other hand, no deletions around the AZFc region were identified in fertile men. Japanese infertile men in our study had a common deletion in the AZFc region of the Y chromosome. A genomic clone was obtained by PCR screening of the P1 phage artificial chromosome (PAC) library. This clone was analyzed by Southern blotting using a PCR amplified probe of sY240. Our analysis of the genomic sequence of the clone suggests that this locus may contain specific genes for spermatogenesis.