Genetic Deletions in Y-Chromosome Contribute to Male Infertility

A study of more than 20,000 men has found that two spontaneously recurring deletions along a complex region of the Y-chromosome are responsible for about 8 per cent of cases of failed sperm production.

The study, conducted by Steven Rozen, an Associate Professor at Duke-NUS Graduate Medical School Singapore and first author of the study in collaboration with Whitehead Institute Director David Page and colleagues has shown that severe spermatogenic failure (SSF) is caused by genetic deletions in the region of the Y-chromosome known as the AZFc (for azoospermia factor c) region. The deletion known as b2/b4 is found in one of every 2,300 men, and it increases the risk of SSF by 145 times.

Associate Prof Rozen noted, “Medically relevant population genetics studies are well established for most of the human genome, but this is the first study of this kind for the Y-chromosome.” The study also relied on a unique sequencing method developed by Rozen and Page to help navigate the structural complexities of the Y-chromosome. The study was published in the American Journal of Human Genetics in November 2012.