Male Infertility - Y-Chromosome Microdeletions
"Infertility affects approximately 1 man in 25 ... Recent studies indicate that genetic causes linked to the Y chromosome, may be important ..." (D. M. Kretser; NEJM 336:576, 1997).
Surveys of infertile males demonstrated that 7% had Y-chromosome deletions of long arm band q11.23. Notably, similar microdeletions were found in 2% of fertile men and in 10% to 15% of men with oligospermia. The Yq11.23 microdeletion relates to RBM (RNA-binding motif) and DAZ (deleted in azoospermia) regions. The DAZ gene in drosophila plays a part in meiosis, a fact suggesting that it may be involved in human spermatogenesis. Other investigators have shown that 13% of men with nonobstructive azoospermia have a microdeletion of the DAZ region (R. Reijo et al. Lancet, 347: 1290, 1996). Intensive research to establish an accurate physical map of the RBM and DAZ gene families is in progress (P.H. Yen, Genomics 54: 5, 1998).