Hyperthyroidism in Down Syndrome

Thyroid conditions, particularly hypothyroidism, are common in people with Down syndrome (DS). Hyperthyroidism is also found at a higher-than-average rate in patients with DS, although only isolated case reports and short series had been published up until now. We recently published the longest series so far examining the relationship between hyperthyroidism and DS. A systematic review of the 1,856 patients seen at Fundació Catalana Síndrome de Down (FCSD) from 1991 to 2006 was undertaken, and 12 cases of hyperthyroidism were diagnosed. The etiological cause was found to be Graves disease in all cases. After initial treatment with antithyroid drugs, all patients required permanent treatment with radioactive iodine I-131. Annual biochemical screening for early diagnosis is less effective than it is for hypothyroidism. Hyperthyroidism may influence growth and development in children with DS; treatment can reverse its impact.