Autoimmune thyroiditis in children with Turner syndrome.

PURPOSE To determine the frequency of autoimmune thyroiditis (AIT) and the risk of development of thyroid dysfunction in children with Turner syndrome. METHODS From 1988 to 1998, 77 children with Turner syndrome were prospectively followed up at National Taiwan University Hospital. The mean (+/- standard deviation) age of these patients was 10.0 +/- 4.7 years at diagnosis of Turner syndrome and 17.4 +/- 5.2 years at the end of the present study. Antithyroglobulin antibody, antimicrosomal antibody, and thyroid function were assessed once every 6 months during the study period. RESULTS Thyroid autoantibodies were detected in 21 of the 77 (27%) patients. The mean age at the detection of thyroid autoantibodies was 12.2 +/- 5.2 years. The cumulative frequency of AIT at 10 years after diagnosis of Turner syndrome was 36%. Both patients with a ring X chromosome developed AIT. Three of the 21 patients (14%) with AIT developed thyroid dysfunction. One patient developed hypothyroidism at the time of the detection of thyroid autoantibody. Two other patients were noted to have hyperthyroidism 0.5 and 2.5 years, after the detection of thyroid autoantibodies, respectively. CONCLUSIONS Our data demonstrated a high frequency of AIT in Taiwanese children with Turner syndrome. Some of these patients later developed thyroid dysfunction. Hence, this study has confirmed that regular follow-up assessment of thyroid autoantibody and thyroid function in Taiwanese children with Turner syndrome regardless of their age is necessary for timely diagnosis of thyroid dysfunction and administration of appropriate treatment.