A newly invented cause of infertility could allow millions of infertile couples universally to have a child. Researchers found a genetic mutation which removes a coating of carbohydrates around sperm, reduces their mobility and could explicate why some men are less fertile than others.
The study revealed that couples who had trouble in conceiving were those where men inherited both copies of this mutant gene that is one from their father and from their mother. Usually, the gene causes the production of a protein called beta-Defensin 126 or BEFB126 that coats the surface of sperm.
But, when gene is mutated, this protein is absent and makes it more difficult for sperm to travel through fluids in the female reproductive tract, which in turn diminishes the rate of conception, explained researchers from the University of California, Davis. Wives of males with the genetic variation were less prone to get pregnant than other couples and were thirty percent less likely to give birth.
The World Health Organization defines infertility as the inability of a couple to conceive after a year of trying and the problem happens with around thirteen to fourteen percent of couples in many countries all over the world. In about half of infertile couples, the cause lies with the men. The study was published in the journal Science Translational Medicine.
Other cause of male infertility is underdeveloped or abnormal sperm, as well as hormone imbalances or certain medications. However, several cases of unexplained infertility are prone to be associated with this genetic variation. Using simple genetic test would soon allow doctors to find genetic mutation easily because normal test like examining sperm under microscope do not detect the mutation.
To test their theory, the scientists conscripted five hundred young couples in China and followed them for nearly two years. The average age of the men was twenty-five and the woman was twenty-three. They were divided into three groups, one with men without gene mutation, second men with one copy of gene mutant gene and third men with both copies of mutation.
The result of study showed that wives of seventy-one percent of men with both copies of mutant gene had conceived, in comparison to eighty-one percent wives of men with one or none of the mutant gene. The rate of births among couples where the husband had two copies of the DEFB126 mutation was thirty percent lower than in other couples.
This most possibly specifies that the DEFB126 mutation reduced the rate of conception in these couples and so it took them longer to achieve pregnancy, explained, Prof Scott Venners from the Simon Fraser University Faculty of Health Sciences. For couples who have the genetic mutation, doctors may consider using more direct interventions such as in vitro fertilization or intrauterine insemination