Genetic Markers Predict Male In-fertility
New study represents a breakthrough in understanding the causes of unexplained male infertility
The diagnosis of male fertility is usually performed by observing sperm under the microscope. However, normal looking semen do not guarantee fertility. In fact, there is a considerable amount of unexplained male infertility and data suggests that abnormal sperm function may begin at the genetic or molecular level.
A study performed by scientists at the Bellvitge Biomedical Research Institute (IDIBELL) and the Puigvert Foundation, both in Spain, has identified a gene fingerprint associated with very low pregnancy rates in semen donors with normal seminal quality.
This genetic fingerprint is a sensitive marker for low sperm fertilizing ability. The results of the study are published in the online edition of the journal Human Reproduction. Technology developed for this project has been protected by a European patent application, and won second prize for best paper at the 29th Congress of the Spanish Fertility Society (SEF) in Granada (Spain).
The study measured patterns of RNA expression (ribonucleic acid) as compared to sperm parameters, on samples from semen donors for intrauterine insemination. The samples were from 68 single, young and healthy donors. Researchers analyzed the expression profiles of 85 genes in the sperm of donors with different rates of pregnancy resulting from intrauterine inseminations.
The selection of these 85 genes was compared with the RNA footprint of normal fertile men already established in previous research. From this comparative analysis, a significant difference in the expression of individual genes was found among eight samples with worse to best pregnancy rates. Researchers found that the expression of four of these genes produced a higher ability to recognize subfertile men than classical analysis of semen (82% vs. 23%). The model was validated by an independent sample of donors.
The study was coordinated by Sara Larriba of the IDIBELL’s Human Molecular Genetics group, and Lluís Bassas, physician/scientist with the Andrology Service at the Puigvert Foundation. Both agree in emphasizing that the results of the study "open the door to advance on the understanding of the causes of infertility of unknown origin and developed in the future an additional test to identify individuals of low fertility despite having normal semen values. This could apply both to the selection of semen donors for the diagnosis of male infertility."
Sandra Bonache, Ana Mata, María Dolores Ramos, Lluís Bassas and Sara Larriba. Sperm gene expression profile is related to pregnancy rate after insemination and is predictive of low fecundity in normozoospermic men. Hum Reprod. 2012 Mar 23. [Epub ahead of print]
Original article: http://www.idibell.cat/modul/news/en/369/identify-genetic-markers-to-predict-male-fertility