Diagnosing cellular defects in an unexplained case of total fertilization failure

Despite the advent of ICSI, cases of total fertilization failure (TFF) often lead to cycle cancellation with limited diagnostic and therapeutic strategies currently available. We report on the case of an infertile couple who failed to conceive after repeated IVF and ICSI. Sperm of the husband were morphologically normal and passed a functional test assessing their ability to activate mouse oocytes. Whether oocytes were activated artificially with calcium ionophore after injection of husband's or with donor sperm, all oocytes failed to fertilize. Multiple polar bodies and two disorganized spindle structures were predominantly observed, pointing towards a cytoplasmic defect in the oocytes as the primary cause of the couple's infertility. In fact, injection of husband's sperm into donor oocytes resulted in the delivery of healthy twins. This report describes a course of action that may be applied for couples with TFF after both IVF and ICSI.