CAPZA3 and Infertility: Studies by Geyer et al., 2019, found that an inactivation point mutation in the Capza3 coding sequence was the cause of infertility in mice possessing an ENU-induced mutation that had been referred to as repro32. Expression of CAPZA3 is testis-specific and mice homozygous for the inactivating repro32 mutation have low epididymal sperm numbers, poor sperm motility, and abnormal sperm morphology59.