Infertility: Sperm need a breakthrough for fertilization

Defective ion channel in sperm flagellum renders men infertile and frustrates medically assisted reproduction. Beating pattern of a human sperm cell before ( left ) und after ( right ) activation of CatSper. The more powerful beat is required to fertilize the egg © University of Münster / Strünker group In half of the couples that are unable to conceive a child, the infertility is due to the man. A new study identifies the defective function of 'CatSper', an ion channel controlling calcium levels in sperm, as a common cause of seemingly unexplained male infertility. CatSper-deficient human sperm fail to fertilize the egg, because they cannot penetrate its protective vestments. Thus far, this sperm channelopathy has remained undetectable. Scientists from Münster, Germany, have unravelled CatSperÂŽs role in infertility using a novel laboratory test that identifies affected men. Based on the results of the study, which has been published in the scientific journal 'The Journal of Clinical Investigation', diagnostics and care of infertile couples can be improved. One in six couples fail to conceive a child. The underlying cause often remains unresolved. In fact, in about one third of infertile couples, the manÂŽs semen analysis yields no abnormalities in the number, motility, or morphology of the sperm. This poses a problem: the lack of a clear diagnosis prevents an evidence-based selection of a therapy option. As a result, affected couples often experience unsuccessful treatments. How do men fail to conceive a child despite normal semen parameters?