ESPE Abstracts

Purpose: Aetiologies of congenital hypothyroidism (CH) in newborn period are various, and TSH receptor (TSHR) mutation is known as one of them. We evaluated mutational analysis of the gene TSHR and clinical characteristics in the patients with CH or neonatal hyperthyrotropinemia.

Method: Mutation analysis was done in 96 children with CH or transient hyperthyrotropinemia who has been managed at the Department of Pediatrics in Dankook University Hospital. Clinical findings including gestational ages, birth weights, total T₃, fT₄, TSH, thyroglobulin as well as thyroid sonography were analysed by the review of their medical records. A P value of <0.05 was considered statistically significant using SPSS software program (version 20.0) and Mann–Whitney U-test, Chi-Square test were used in the study.

Result: A total of 96 subjects were included in the study. 89 were diagnosed as having CH and seven were as having transient hyperthyrotropinemia. TSHR gene mutation was detected in 12 subjects (12.5%). R450H was the most common (n=4), followed by R519C (n=2), C390F (n=2), R531W, G245S, I81N, S305R. C390F, I81N, and S305R were the novel mutations. One subject with S305R mutation showed ectopic thyroid. There were no statistically significant differences in age at TSH elevation, gender, birth weights, findings of thyroid sonography, and the levels of total T₃, fT₄, TSH, thyroglobulin between a group with TSHR mutation and a group without TSHR mutation. Thyroid hormone replacement was continuously required in four children (44.4%) among nine subjects with TSHR mutation who were followed over 3 years of age.

Conclusion: This study showed that the mutation of TSHR gene is the common cause of CH. Although there were no statistically significant differences of clinical characteristics between patients with TSHR mutation and those without mutation, more than half of patients with TSHR mutation could discontinue the replacement of thyroid hormone after 3 years of age.