KCTD19 and Azoospermia: Although KCTD19 [46] and LRRC36 [47] genes are mainly expressed in the testis and could not be directly associated with POI phenotype, KCTD19 knockout mice produced spermatocytes that failed to complete meiosis, leading to azoospermia, indicating its role in meiosis and, putatively, gametogenesis in general [46].