United detection GNAS and TSHR mutations in subclinical toxic multinodular goiter.

The aim of the study was to investigate whether the mutations of the GNAS gene and thyroid-stimulating hormone receptor (TSHR) gene were a potential molecular biological mechanism for subclinical toxic multinodular goiter (sTMG) and to evaluate the association of these mutations with the clinicopathological features of these disorders.Forty-four patients with sTMG and 20 controls(multinodular goiter) from Heilongjiang province of China who underwent subtotal thyroidectomy were recruited. Genes' mutations were analyzed by direct DNA sequencing of the polymerase chain reaction-amplified the parts of exons. In sTMG group, three mutations at GNAS gene were identified in seven patients (15.9%). Six mutations at TSHR gene were identified in 14 patients (31.8%). Mutation positivity of TSHR gene had statistically significant by comparison of two groups. In sTMG group, the mutation positivity of patients with serum TSH level below 0.1 microU/ml and above 0.01 microU/ml is obviously different (P < 0.05) at TSHR gene. However, these statistically significant differences were both not being seen at GNAS gene, and patients with nodules before universal salt iodization (USI)and after USI (P > 0.05). Mutation positivity of TSHR gene has a relation with sTMG. It is more probable that serum TSH level play an important role in mutagenesis.