Faulty gene may cut short male fertility

A gene mutation could curtail sperm production and lead to early loss of fertility in men, says a study.

The study determined that loss of the gene that makes the protein TAF4b in male mice results in the premature exhaustion of their fertility.

The researchers noted that the process of sperm generation in mice may have direct applications to a similar loss of fertility in men.

"What is fascinating about these mice is they can reproduce," said senior study author Richard Freiman from Brown University in the US.

"Mice can usually reproduce until they are two years old, but these mice can only reproduce until they are four months old," said Freiman.

What the team discovered is that the loss of the gene that makes the protein TAF4b causes a deficit in the number of progenitor cells at an embryonic stage of a male mouse's reproductive development.

Lacking those important precursor cells means that the mice struggle to develop a robust stem cell infrastructure to sustain sperm production for the long term.

The affected mice are fertile at first, but quickly deplete the limited sperm supply that they can generate, the researchers pointed out.

TAF4b is a protein that affects how genes are regulated and transcribed, and its absence has profound impact on the reproductive system.

In previous work, Freiman's research group has shown that female mice without TAF4b are totally infertile and that their ovaries age prematurely.

Not only do humans have a gene for TAF4b, but a study last year in the Journal of Medical Genetics provided evidence that it also matters for sperm count, the researchers pointed out.

The new study appeared in the journal Stem Cells.