THE ESSENTIAL
- 29 mutations (which are not inherited from the mother and father) on genes that play a role in male reproduction could cause male infertility.
- Exposure to pollutants and toxins in the environment can have a direct detrimental effect on sperm, which causes a decrease in their number and impairs their quality, resulting in male infertility.
In France, one in eight couples consults a doctor because of difficulties in conceiving a child, according to l’Inserm. We speak of infertility in a couple when a pregnancy does not occur after 12 to 24 months of full, regular sexual intercourse without contraception. “In three quarters of cases, infertility is of male or female origin, or it associates both sexes. In 10 to 25%, it is not attributable to a specific defect of one of the two partners”, says Inserm.
According to health insurance, all factors of male infertility are not yet known. The World Health Organization (WHO) indicates that, in men, this condition of the male reproductive system is caused by a decrease in the number and motility of spermatozoa or the absence of spermatozoa in the semen. Genetic factors could drive these two main mechanisms. Recently, researchers from the University of Newcastle in the UK discovered a new cause of male infertility. Their results were published in the journal Nature Communications.
“29 de novo mutations that could be the cause of male infertility”
“De novo mutations (i.e. not present in the parents) are known to play an important role in sporadic disorders. We speculate that de novo mutations play an important role in male infertility and explain some of the genetic causes of this little-studied disorder”, they specified.
For the purposes of their work, the scientists collected the DNA of 185 people. Among the participants are infertile men and their parents. “After analysis, 29 of 145 rare de novo protein-altering mutations are classified as possibly causing male factor infertility,” can we read in the study. The researchers specified that these mutations occur “during DNA replication during reproduction”.
The 29 mutations identified by the research authors relate to genes known to play a role in male reproduction. For the moment, they do not know how these mutations can have an impact on the development of spermatozoa by the testicles. But the team reported that there is a 50% chance that infertility caused by these mutations will be passed on to the children of infertile men, which can lead to infertility from generation to generation.