Abstract: Objective To explore the clinical manifestations and genetic characteristics of non-autoimmune hyperthyroidism. Methods The clinical data and gene sequencing results of non-autoimmune hyperthyroidism in a child were retrospectively analyzed. Results A 9 -month-old boy had a rapid heart rate as the main manifestation, combined with general developmental retardation and congenital heart disease, etc. Laboratory tests showed that the level of thyroid stimulating hormone was decreased, the levels of free triiodothyronine and free thyroxine were increased, and all related antibody tests were negative. The missense mutation of c. 1894 A>G (p.T 632 A) in exon 10 of TSHR gene was found by gene detection. It was a new mutation and had not been reported. It was predicted to be pathogenic by software. After oral treatment with methimazole, thyroid function was significantly improved and developmental retardation was improved. Conclusion Gene detection is beneficial to the diagnosis of non-autoimmune hyperthyroidism

Key words: non-autoimmune hyperthyroidism; TSHR gene; growth retardation