GnRH Deficient Patients With Congenital Hypogonadotropic Hypogonadism: Novel Genetic Findings in ANOS1, RNF216, WDR11, FGFR1, CHD7, and POLR3A Genes in a Case Series and Review of the Literature.

Background: Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic disease caused by Gonadotropin-Releasing Hormone (GnRH) deficiency. So far a limited number of variants in several genes have been associated with the pathogenesis of the disease. In this original research and review manuscript the retrospective analysis of known variants in ANOS1 (KAL1), RNF216, WDR11, FGFR1, CHD7, and POLR3A genes is described, along with novel variants identified in patients with CHH by the present study. Methods: Seven GnRH deficient unrelated Cypriot patients underwent whole exome sequencing (WES) by Next Generation Sequencing (NGS). The identified novel variants were initially examined by in silico computational algorithms and structural analysis of their predicted pathogenicity at the protein level was confirmed. Results: In four non-related GnRH males, a novel X-linked pathogenic variant in ANOS1 gene, two novel autosomal dominant (AD) probably pathogenic variants in WDR11 and FGFR1 genes and one rare AD probably pathogenic variant in CHD7 gene were identified. A rare autosomal recessive (AR) variant in the SRA1 gene was identified in homozygosity in a female patient, whilst two other male patients were also, respectively, found to carry novel or previously reported rare pathogenic variants in more than one genes; FGFR1/POLR3A and SRA1/RNF216. Conclusion: This report embraces the description of novel and previously reported rare pathogenic variants in a series of genes known to be implicated in the biological development of CHH. Notably, patients with CHH can harbor pathogenic rare variants in more than one gene which raises the hypothesis of locus-locus interactions providing evidence for digenic inheritance. The identification of such aberrations by NGS can be very informative for the management and future planning of these patients.

46,XY complete gonadal dysgenesis in a familial case with a rare mutation in the desert hedgehog (DHH) gene.

PURPOSE: Disorders of sex development (DSD) have been linked to gene defects that lead to gonadal dysgenesis. Herein, we aimed to identify the genetic cause of gonadal dysgenesis in a patient with primary amenorrhoea tracing it to a phenotypic female carrying a 46,XY karyotype of a consanguineous family. METHODS AND RESULTS: Whole exome sequencing (WES) was performed and revealed in homozygosity the rare and only once reported p.Arg164Pro missense mutation in exon 2 of the desert hedgehog (DHH) gene. Sanger sequencing was used to validate this candidate variant both in the patient, the parents, and two siblings. Both brother and sister of the index patient were found negative for the p.Arg164Pro mutation, while the consanguineous parents were found to carry the mutation in the heterozygous state. Neither the parents nor the unaffected siblings showed any reproductive malformations. CONCLUSIONS: Defects in the DHH gene have been reported as a very rare cause of DSD, and this report increases the number of 46,XY gonadal dysgenesis cases. Additionally, the present study highlights the importance of genetic validation of patients with DSD, since this is likely to alleviate the considerable psychological distress experienced by both the patient and the parents.