Bi-allelic KCTD19 variants associated with meiotic arrest and non-obstructive azoospermia in humans

Non-obstructive azoospermia (NOA) represents the severe form of male infertility, affecting approximately 1% of men during their reproductive years. It is marked by the absence of sperm production caused by testicular dysfunction and has many genetic origins. However, the genetic factors underlying most NOA cases are still unclear. Meiosis, a crucial process ensuring accurate chromosome segregation and generating genetic diversity in gametes, is susceptible to genetic disruptions that may result in NOA. In this study, whole exome sequencing (WES) was conducted on 969 NOA patients, identifying six compound heterozygous KCTD19 variants in three Chinese pedigrees. KCTD19 has been demonstrated to interact with ZFP541 and HDAC1, thereby participating in the modulation of chromatin remodeling and transcriptional programs during meiosis in mice. Herein, our findings expand the phenotypic and mutational spectrum of KCTD19 in male infertility and provide further insights into its role during meiosis. This research underscores the importance of KCTD19 in meiotic progression and male fertility, highlighting the need for further investigation into the molecular mechanisms underlying gametogenic failure in NOA.