[Genetic analysis of a Chinese pedigree affected with Isolated growth hormone deficiency due to variant of CHRHR gene].

OBJECTIVE

To analyze the clinical and genetic characteristics of a Chinese pedigree affected with congenital Isolated growth hormone deficiency (IGHD).

METHODS

A pedigree presenting with Pituitary stalk interruption syndrome (PSIS) (including the proband, his two younger sisters and both parents) who had visited the Capital Institute of Pediatrics Affiliated to Capital Medical University in September 2020 was selected as the study subject. Clinical data were collected. Peripheral blood samples were collected from the proband and his family members. Following the extraction of genomic DNA, whole-exome sequencing (WES) was carried out, and candidate variants were validated by Sanger sequencing. The pathogenicity of the candidate variants was classified based on guidelines from the American College of Medical Genetics and Genomics (ACMG). This study was approved by the Medical Ethics Committee of the Institute Pediatrics of Capital Medical University (Ethics No.: SHERLL2025033).

RESULTS

The proband and one younger sister (Ⅱ3) presented with growth retardation, short stature, and a doll-like facies. Another younger sister (Ⅱ2) and both parents had normal heights and appearance. Sanger sequencing confirmed that the proband and his younger sister (Ⅱ3) both harbored compound heterozygous variants of the GHRHR gene, namely c.776C>A (p.T259K) and c.1166G>A (p.R389Q). The other younger sister (Ⅱ2) and the parents were heterozygous carriers. The c.1166G>A (p.R389Q) variant was unreported previously. Based on the guidelines from the ACMG, it was classified as variant of uncertain significance (PM2_Supporting+BP4). Bioinformatics analysis indicated a deleterious effect on the protein function.

CONCLUSION

Variants of the GHRHR gene probably underlay the pathogenesis of IGHD in this pedigree. Above finding has provided a basis for the clinical diagnosis and genetic counseling for this family.