Transient thyrotoxicosis in an infant delivered to a long-acting thyroid stimulator (lats)- and lats protector-negative, thyroid-stimulating antibody- positive woman with hashimoto’s thyroiditis

A thyrotoxic infant was delivered to a womanwith a long-standing history of Hashimoto’s thyroiditis, but withno evidence of Graves’ disease. Long-acting thyroid stimulator(LATS) and LATS protector were absent, but thyroid-stimulatingantibody was transiently present in the infant and markedlyand persistently elevated in the mother. It is concluded that the maternal level of thyroid-stimulating immunoglobulins determinesthe presence and duration of transient neonatal thyrotoxicosis, and that thyroid-stimulating antibody is distinct from LATS and LATS protector.