Male infertility gene discovered

Scientists from the Pasteur Institute in France and University College London have discovered the gene that causes infertility in men.

Mutations in the NR5A1 (nuclear receptor subfamily 5, group A, member 1) gene were found in a small percentage of infertile men.

The gene was known to be involved in sexual development in both men and women and linked with physical defects in the development of the testicles or ovaries.

"Given the complexity of the sperm production process it is likely that many genes are involved," BBC quoted Allan Pacey, senior lecturer in andrology at the University of Sheffield, as saying.

In a group of 315 apparently healthy men, the team found mutations in the gene in just seven, and closer examination revealed that the men had altered levels of sex hormones and, in one case, mild abnormalities in the cellular structure of the testicles was seen.

"We concluded that approximately 4% of men with unexplained failure to produce sperm carried mutations in the NR5A1 gene,"  said the researchers.

"Though this gene defect affected only a small number of men, we need more studies like this so that we can fill the gaps in our knowledge and possibly one day build a robust diagnostic test for male fertility based on genetics," said Pacey.

The study was published in the American Journal of Human Genetics.