Acquired sperm DNA alterations can cause chromosomal abnormalities in embryos, fetuses and offspring, according to a study recently published in the British European Medical Journal by Dr. Jan Tesarik, director of the MARGen clinic in Granada (Spain).
Until now, it was believed that sperm DNA fragmentation was a cause of infertility and spontaneous abortions but not of chromosomal abnormalities of embryos, fetuses and born children, which were attributed to the ovules.
According to different sources, the prevalence of infertility caused by sperm DNA fragmentation is between 10% and 20%. If one considers that, in 50% of cases of infertility in the couple, the origin is in the man, this fragmentation is very relevant in the context of male infertility and the health of the offspring.
The DNA molecule is composed of two chains linked one with the other in a specific way. Acquired sperm DNA abnormalities are caused by the breakage of one or both chains. When only one chain is broken, it can be corrected from the other chain, but breaks in both chains are more serious.
According to the study, the clinical importance of DNA fragmentation is assessed by determining the percentage of affected sperm. Even fertile men have some sperm with fragmented DNA. The percentage of affected sperm determines if the man is fertile. In cases of abnormal values, and if the cause is identified, for example, an infection or smoking, the specific treatment (antibiotics or smoking cessation for a few months) can itself fix the problem.
If the cause is not identified, there are different options, from little invasive treatments (vitamins and other antioxidant substances by mouth) to testicular biopsy in resistant cases. Another option is the selection of “healthy” sperm in the laboratory.
“It is essential,” says Dr. Tesarik, “to correctly assess the condition of each patient and confront it with the fertility status of their partner, since the ovules of young women can repair the fragmented parts of the sperm’s DNA when it is in its interior; however, this ability of the ovules is gradually lost with age“.
According to the author, “the egg always tries to repair any sperm DNA problem, but this activity sometimes causes more damage than benefits. If there is an error in the reparative process and embryos survive until birth, children can be born with several chromosomal abnormalities, such as trisomies of chromosomes 21 (Down syndrome), 18 and 13, X chromosome monosomy in girls born (Turner syndrome) and various types of translocations.”
In his conclusions, Tesarik points out that embryos created with sperm with high rates of DNA fragmentation should have the same risk consideration of chromosomal abnormalities as those conceived with ovules of women in advanced ages.
Source: Agencia ID