Identification of a novel TSHR mutation from a Chinese baby with congenital hypothyroidism due to ectopy

Background: Congenital hypothyroidism (CH) is characterized by elevated levels of TSH with simultaneous low serum T4 and T3 levels because of reduced thyroid function. About 85% of CH cases are associated with thyroid dysgenesis, but its pathogenesis remains unclear. Aim: To screen TSHR mutations in Chinese CH patients with ectopy. Materials and methods: After collecting blood samples from 89 CH babies with ectopy, genomic DNA was extracted and exon 10 in TSHR mutations were detected by PCR as well as direct sequencing. Results: A novel missense mutation c.1270G>A, which results in the substitution of a valine at position 424 by an isoleucine residue (p.Val424Ile) was found according to direct sequencing of 89 subjects. Conclusion: We report a novel heterozygous missense mutation in one out of 89 unrelated Chinese CH patients with ectopy.