Congenital hyperthyroidism caused by a mutation in the thyrotropin-receptor gene

Congenital hyperthyroidism is rare. Most cases occur in infants born of mothers with a history of Graves' disease.¹ The disorder is usually transient in such infants, because it is caused by transplacental passage of maternal thyrotropin-receptor–stimulating autoantibodies that are subsequently cleared.^2,3 However, a few neonates with persistent nonautoimmune hyperthyroidism of unknown cause have been described.⁴–¹¹ The family history suggested an autosomal dominant disorder in some of these infants.^5,12 A molecular basis for autonomous thyroid function has been found in some patients with hyperfunctioning thyroid adenomas. Some of these tumors have somatic mutations in stimulatory G (guanine nucleotide–binding).  . .