Molceular genetics of Y chromosome in male infertility

Abstract

Y chromosomal microdeletions at the AZF locus (Yq11) have been implicated as one of the major causes of idiopathic male infertility. This study has found that among 511 infertile men in Singapore, prevalence of Y-microdeletions was 2.9% and present in 4.1% of azoospermic and 2.8% of severely oligozoospermic men. DAZ and VCY2 genes are the most commonly deleted followed by RBMY1. A point mutation in Androgen Receptor gene together with DAZ deletions caused severe oligospermia in a man; DYZ1 and Yq12 deletions resulted in germ cell hypoplasia in an individual and; an azoospermic man had deletion of an exon in VCY2. This study, the first in Singapore and South-east Asia, has established that 1) there is a cause-and-effect relationship between de novo Y-microdeletions and male infertility but no define phenotype for particular pattern of Y-microdeletions; 3) germinal mosaicisms are present but uncommon; 4) Y-microdeletion analysis by STS-PCR is a useful diagnostic tool in identifying Y-deleted men so that proper counseling can be given before treatment by ICSI that carries the risk of transmission of Y-microdeletions from father to son.