0948 GMT January 21, 2019
Oftentimes, men with azoospermia don't know the underlying cause of their condition. But new research, led by University of Pennsylvania, suggests that mutations in an X chromosome gene called TEX11 are responsible for a significant number of cases of infertility, an estimated one percent of cases of non-obstructive azoospermia, scifeeds.com wrote.
To experimentally test whether the mutations that were identified in infertile men were the reason for their azoospermia, the research team selected three mutations found in the azoospermic men but not in the controls. They then engineered mice with versions of Tex11 that bear those same mutations and experimentally bred mice to express those mutated versions.
For two of these mutations, they saw little effect. But the third had striking effects: Males with this variant had significantly lower sperm counts than control animals. In addition, these mice had abnormalities in meiosis.
In total, from the screening of 275 men, researchers found three mutations in TEX11 that appeared to be the cause of the infertility, resulting in a rate of about 1 percent of cases of azoospermia.
"Given that there are hundreds of candidate genes for male infertility," Jeremy Wang, lead author of the study, said, "one percent is actually very significant."
As a trend toward personalized medicine means that more people can have portions or the entirety of their genome sequenced, these results have implications for genetic counseling for infertility.
"If men had one of these same mutations in this gene, I think we could safely say that's the cause of their infertility," Wang said.