Scientists have identified a new genetic variant they believe is linked to male infertility.
The study was led by Dr Pille Hallast of the University of Tartu, Estonia. Male infertility affects up to 10% of men but few genetic factors have been found, so Dr Hallast and her team searched the genome for possible links.
They looked specifically at an area of the Y chromosome called the Azoospermia Factor c (AZFc) region, alongside three other genes linked to fertility.
The team analysed the genetics of 2,324 men, of whom about half had unexplained male infertility, and uncovered a new variant as a risk factor for male infertility.
A specific gene variant, which is found in about 20% of Central and Eastern European men, was found to destabilise the AZFc region. The variant also appears to encourage large recurrent microdeletions of genetic information.
It was more than eight times more likely to be present in men with infertility problems, reported the team in eLife journal yesterday (30 March).
"This finding contributes to improved molecular diagnostics and clinical management of infertility," they write. "Carrier identification at young age will facilitate timely counselling and reproductive decision-making."
Dr Hallast said: “Our study is the largest, most sophisticated look at the genetic variation of this particular Y-chromosomal region that can increase the risk of impaired sperm production in men.
"We identified a common Y-chromosome subtype that is susceptible to genetic changes leading to low sperm count, but also can go unnoticed and passed down in families until a deletion in this genomic region occurs.”
Co-author Professor Maris Laan added: “Being able to identify the genetic reason for these men having impaired sperm production will help give them a diagnosis and access to the support that this brings."
Hallast, P. et al. A common 1.6 Mb Y-chromosomal inversion predisposes to subsequent deletions and severe spermatogenic failure in humans. eLife journal 30 March 2021
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