Prevalence of thyroid disorder in Down syndrome.

Thyroid function has been studied in 121 patients between 13 and 48 years old with proven Down syndrome. Chemically, hypothyroidism was found in 17% and hyperthyroidism in 2.5% of the patients; 18% of patients had goiter. Thyroid antibodies were detected in 33% of subjects studied. The abnormal findings were almost equally distributed between the sexes above 20 years of age; however, females had significantly more thyroid disease than males in the younger age group.