Asthenozoospermia is a common pathogenesis of male infertility. The motility of spermatozoa is based on the presence of an intact flagellum and an adequate energy supply. The midpiece of the human spermatozoa consists of the axoneme and the outer wrapped mitochondrial sheath, which is essential for sperm motility. Here, we identified bi-allelic ARMC12 mutations from three infertile patients with multiple flagella defects in the midpiece, including absent MS and central pair, scattered or forked axoneme, and incomplete plasma membrane. Spermatozoa from Armc12^-/- mice showed parallel defects in the midpiece. Our findings prove for the first time that defects in ARMC12 cause asthenozoospermia and multiple midpiece defects in humans and mice. Moreover, intracytoplasmic sperm injection could achieve good outcomes. This study indicated that we need to pay more attention to the morphological defects in the midpiece of the sperm flagella in patients with asthenozoospermia.

These results may further facilitate genetic counselling, pregnancy expectancy and offspring health risk assessment for clinicians and patients with asthenozoospermia due to multiple midpiece-specific defects. (By Professor Yifeng Wang, https://jmg.bmj.com/content/early/2022/05/08/jmedgenet-2021-108137 )