Infertility, defined as the failure to conceive after a year of unprotected intercourse, affects one in every six couples worldwide, and the man is implicated in about half of these cases. Despite the known importance of genetic factors in the event of the man producing no sperm, only about 25% of these cases can be explained currently. A study presented recently at the annual conference of the European Society of Human Genetics has uncovered new potential genetic causes, and this discovery will help to develop better diagnostic tests for male infertility.
Researchers from the Radboud University Medical Centre, Nijmegen, the Netherlands, carried out the first exome sequencing study to investigate the role of “de novo” mutations (genetic changes that are not present in the DNA of the parents of an individual) in male infertility. The exome is the DNA sequence of genes that are translated into protein, where most of the currently known disease-causing mutations are situated.
De novo mutations are found in every individual and are part of the normal evolution of the genome, and usually do not affect our health, the researchers explained. But in some cases they have a strong effect on gene function and can lead to disease. Until now, their role in male infertility had not been studied.
The researchers studied DNA from 108 infertile men, and also from their parents. Comparing the parental DNA with that of the offspring enabled them to identify 22 genes involved in de novo mutations. The researchers hope to screen more patients and their parents in order to search for patterns in the locations of the novel mutations, and to learn more about the function of the genes that are affected by them.
The results will help establish new diagnostic tests, which will be able to provide a patient with a detailed analysis of the reason for his infertility, and allow for personalized care.