However, carriers with MCM8 loss-of-function homozygous variants display gonadal dysgenesis, presenting as invisible or very small ovaries and primary amenorrhea in POI patients (AlAsiri et al, 2015; Bouali et al, 2017; Tenenbaum-Rakover et al, 2015) and as Sertoli-cell-only syndrome instead of spermatogenic arrest at the meiotic stage in NOA patients (Kherraf et al, 2022). The gene discussed is MCM8; the disease is Sertoli Cell-Only Syndrome.