A novel splice site variant in ANOS1 gene leads to Kallmann syndrome in three siblings.

Idiopathic hypogonadotropic hypogonadism (IHH) is a rare genetic disease caused by low doses of hypothalamic gonadotropin-releasing hormone (GnRH), leading to absence or delayed sexual development. Kallmann syndrome (KS) is characterized by IHH with anosmia or hyposmia. Here, we identified a novel splice site variant (c. 726+2T>G) of ANOS1 gene in three siblings with KS from a Chinese Han family by whole-exome sequencing (WES). In this family, KS is classified as an X-linked recessive inheritance pattern. This mutation was inherited from the mother by Sanger sequencing. An in vitro functional experiment has identified the deleterious effect of this mutation on the transcriptional level of ANOS1 gene. Importantly, the effectiveness of timely hormone replacement therapy was evaluated on the three siblings. Hence, finding genetic causes could be helpful in the early diagnosis and timely treatment of KS.