Incidence and dynamics of thyroid dysfunction and thyroid autoimmunity in girls with Turner's syndrome: a long-term follow-up study.

OBJECTIVE: Clinical studies suggest that the thyroid autoantibodies and/or hypothyroidism are not present in Turner's syndrome (TS) patients before the age of 8 years and are more frequent in patients with the X isochromosome. The aim of the study was to analyze the dynamics of thyroid dysfunction in girls with TS.
DESIGN: 86 TS patients with a median age of 10.6 years were followed for 4.6 ± 3.0 years. OUTCOMES: The prevalence of thyroid abnormalities increased from 25.5 to 50% during the follow-up. Finally, 31 (36%) patients had positive thyroid autoantibodies and 27 (31.4%) had subclinical hypothyroidism. Hashimoto's thyroiditis was diagnosed in 15 patients. Median age of developing thyroid antibodies and subclinical hypothyroidism was 14.1 and 14.8 years, respectively. The youngest hypothyroid patient was 1.8 years old and the youngest girl with positive anti-thyroid antibodies was 5.5 years old. Autoantibodies appeared mainly after the age of 13. The risk of developing subclinical hypothyroidism was greatest between 12 and 14 years of age. The prevalence of thyroid abnormalities was not related to the karyotype.
CONCLUSIONS: Thyroid autoimmunity and dysfunctions in TS may start early, their prevalence increases with age, independently of karyotype and without any clinical symptoms and signs.