Spermatogenesis is an ongoing developmental process in adult testes that requires the coordinated expression of many genes. The genetic causes of spermatogenic failure in men remain largely unknown, though abnormalities in the sex chromosomes constitute a significant portion of them. In this review, we focus on 3 disorders that involve the sex chromosomes and are often screened in infertility clinics. These are Klinefelter syndrome, Y chromosome microdeletion, and XX male syndrome. We describe their prevalence, the associated phenotypes, and the molecular mechanisms underlying the disorders and discuss the difficulties in identifying the causal genes contributing to the spermatogenic defects. Currently, there are no effective therapies for the spermatogenic failure in the patients, and conception through assisted reproductive technology bears the risk of passing genetic abnormalities to the next generation.
(c) 2008 S. Karger AG, Basel.