Thyrotropin receptor and thyroid transcription factor-1 genes variant in Chinese children with congenital hypothyroidism.

The aim of the present study was to investigate the mutation/variant of thyrotropin receptor (TSHR) and thyroid transcription factor-1 (TTF-1) genes in Chinese children with congenital hypothyroidism (CH). Seventy-nine and forty-nine Chinese children with CH were enrolled for molecular analysis of the TSHR gene and TTF-1 gene, respectively. One hundred normal children were evaluated as control. The coding regions of TSHR and TTF-1 genes were amplified by polymerase chain reaction and sequenced. Sequencing of the TSHR gene revealed a compound heterozygous variants (Pro52Thr/Val689Gly) and a heterozygous variant (Gly245Ser) in 2 of 79 patients. In 30 patients and 33 controls the normal cytosine at position 2181 in exon 10 of TSHR gene was replaced by a guanineCresulting in the replacement of Asp (727) by Glu. In 47 patients and 50 controls, the normal thymidine at position 561 in exon 7 of TSHR gene was replaced by a cytosine. This substitution did not change the amino acid in position 187. Sequencing of the TTF-1 gene revealed no mutation or polymorphism in 49 patients and 100 controls. In conclusion, three heterozygous variants (Pro52Thr, Gly245Ser, Val689Gly) of TSHR gene were firstly detected in Chinese children with CH. There were polymorphisms in exon 10 at nucleotide 2181 (C/G) and in exon 7 at nucleotide 561 (T/C) in TSHR gene. No mutation or polymorphism was detected in the coding region of TTF-1 gene. The mutation/variant of TSHR and TTF-1 genes is relatively rare in Chinese children with CH.