Male infertility has many causes and ejaculate that contains no sperm is a rare condition, and one that doctors can do little to treat. They often cannot even determine the cause of non-obstructive azoospermia, the complete absence of sperm cells in a man's ejaculate, in the roughly 1 percent of men who suffer from the condition.
Now a team of Israeli scientists in Be’er Sheva has identified a mutation in the gene called TDRD9 causing this form of infertility, which is believed to affect anywhere from five to twenty percent of infertile men.
The scientists found that five men from a Bedouin tribe in the Negev with the condition all had the same type of mutation in the TDRD9 gene. The mutation does not cause infertility in women, noted the researchers from Ben-Gurion University of the Negev and Soroka Medical center.
A better understanding of why some men cannot produce sperm hasn’t yet led to a cure, but treatment may be possible in the future.
Azoospermia surfaces during puberty, when sperm production begins, says paper co-author Professor Eitan Lunenfeld, head of the infertility and in vitro fertilization unit at Soroka. Sometimes “no sperm count,” as the condition is often called, originates in the brain's pituitary gland. In such cases, the infertility can be treated. In most cases, however, the condition is results from problems in the testes, where the body produces sperm.
In the study, tissue samples of five participants with sperm-cell free ejaculate were given to the Soroka unit, Mahmoud Huleihel and Ruti Parvari of Ben-Gurion University for testing. The tests for TDRD9 were based on prior research on mice showing a correlation between the gene and sperm production.
When TDRD9 functions correctly, it is believed to play a key role in monitoring the process of producing sperm. When the gene is mutated, this process is halted.
In the study, samples of ejaculate without sperm cells belonging to five participants were given to the Soroka unit gave tissue samples from their testicles to Mahmoud Huleihel and Ruti Parvari of Ben-Gurion University. Their tests of TDRD9 were based on prior research in mice that showed a correlation between the gene and sperm production.
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