“…While deletions or small mutations in USP9Y seem to be associated with severe hypo-spermatogenesis only, patients with deletions of DBY may present with a combination of the two: sertoli cell-only syndrome (SCOS), a condition characterized by the presence of complete Sertoli cells in the testes but a lack of spermatozoa in the ejaculate and severe hypospermatogenesis [17,48]. On the contrary, patients with deletions of both USP9Y and DBY seem to invariably demonstrate azoospermia with a testicular histology of SCOS [17,49]. Deletion of the USP9Y gene can additionally cause azoospermia, oligozoospermia, or oligoasthenozoospermia [15,50].…”