[Clinical feature and genetic analysis of a patient with Idiopathic hypogonadotropic hypogonadism due to a novel variant of CHD7 gene].

Objective: To explore the clinical feature and genetic etiology of a patient with normosmic idiopathic hypogonadotropic hypogonadism (nIHH) due to variant of CHD7 gene.

Methods: A patient who had presented at Anhui Provincial Children's Hospital in October 2022 was selected as the study subject. Clinical data of the patient was collected. The patient and his parents were subjected to trio-whole exome sequencing. Candidate variant was verified by Sanger sequencing and bioinformatic analysis.

Results: The patient had featured delayed development of secondary sexual characteristics but normal olfactory function. Genetic testing revealed that he has harbored a c.3052C>T (p.Pro1018Ser) missense variant of the CHD7 gene, for which both of his parents were of the wild type. The variant has not been recorded in the PubMed and HGMD databases. Analysis of amino acid sequences suggested that the variant site is highly conserved, and the variant may affect the stability of protein structure. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.3032C>T variant was classified as a likely pathogenic (PS2+PM2_Supporting+PP2+PP3+PP4).

Conclusion: The delayed development of secondary sexual characteristics of the patient may be attributed to the c.3052C>T (p.Pro1018Ser) variant of the CHD7 gene. Above finding has expanded the variation spectrum of the CHD7 gene.