LRRC23 deficiency causes male infertility with idiopathic asthenozoospermia by disrupting the assembly of radial spokes.

Asthenozoospermia (AZS) is the primary cause of infertility in males. The radial spoke (RS) is an axonemal structure, connecting the peripheral doublet microtubules with the central pair of microtubules. This T-shaped multiprotein complex functions as a mechanochemical sensor to promote sperm motility. LRRC23 is a novel subunit of the RS complex that is necessary for flagellar assembly and movement in mice. However, the importance of LRRC23 in modulating RS formation in humans remains unclear. Here, we identified a homozygous nonsense mutation in LRRC23 (c.376C>T:p. Arg126X) in an infertile AZS patient whose parents were consanguineous. We verified the adversity of this novel mutation because of its ability to disrupt LRRC23 synthesis and impair RSs integrity. Furthermore, we demonstrated an interaction between LRRC23 and RSPH3 in vitro, indicating that LCCR23 is associated with RS in humans. Meanwhile, the LRRC23-mutant patient had a good prognosis following intracytoplasmic sperm injection. This study provides strong preliminary evidence that LRRC23 defects are potential causative factors of AZS in humans, which expands our knowledge for improved genetic counseling and better reproductive recommendations for patients with AZS.