Mutation screening of the GLIS3 gene in a cohort of 592 Chinese patients with congenital hypothyroidism

Objectives: Defects in the human GL1-similar 3 (GLIS3) gene are reported to be a rare cause of congenital hypothyroidism (CH) and neonatal diabetes. The aim of this study was to examine the prevalence of GLIS3 mutation among CH patients in the Guangxi Zhuang Autonomous Region of China and to define the relationships between GLIS3 genotypes and clinical phenotypes. Methods: Blood samples were collected from 592 patients with CH in Guangxi Zhuang Autonomous Region, China, and genomic DNA was extracted from peripheral blood leukocytes. All exons of the GLIS3 gene with their exon-intron boundaries were screened by next-generation sequencing (NGS) and CNVplex (R). Chromosomal microarray analysis (CMA) was performed to detect the existence of the adjacent gene deletion. Results: NGS and CNVplex (R) analysis of GLIS3 in 592 CH patients revealed two different variations in two individuals (2/592, 0.3%). Patient 1 was the paternal allele of 9p24.3p23 heterozygous deletion including the whole GLIS3 gene, and patient 2 was heterozygous for c.2159G > A (p.R720Q) GLIS3 variant combined with compound heterozygous DUOX2 mutations (p.R683L/p.L1343F). Conclusions: Our study indicated that the prevalence of GLIS3 variations was 0.3% among studied Chinese CH patients. Multiple variations in one or more CH associated genes can be found in one patient. We found a novel GLIS3 variation c.2159G > A (p.R720Q), thereby expanding the variation spectrum of the gene.