Alteration of spermatogenesis and Y chromosome microdelations. Analysis of the DAZ gene family

The Y chromosome has a fundamental role in sex determination and regulation of spermatogenesis. Three regions (designated as AZFa, b, and c) on the long arm of this chromosome exist, deletions of which result in severe damage to spermatogenesis with azoospermia or severe oligozoospermia. Recent progresses in molecular biology and extraordinary development of assisted reproduction techniques contributed to the research on this chromosome and the genes involved in spermatogenesis. About 10-15% of subjects affected by azoospermia or severe oligozoospermia carry a deletion in one or more AZF regions, 60% of which involves AZFc. The genes responsible for the testicular phenotype observed in these subjects are DBY and USP9Y for AZFa, RBMY1 for AZFb, and DAZ for AZFc. In this article, the current knowledge on biology and genetics of the Y chromosome are reported with particular interest to deletions found in infertile subjects. Furthermore, the more recent advances on DAZ gene and its role in spermatogenesis and male infertility are discussed.