Neonatal hyperthyroidism is a relatively uncommon disorder. It has been described in infants born to women with active hyperthyroidism and in those born to euthyroid women previously treated medically or surgically for hyperthyroidism.1 Recent evidence suggests that neonatal hyperthyroidism is due to thyroid stimulation in the fetus by a transplacentally acquired long-acting thyroid stimulation globulin (LATS) or a human specific antibody, LATS-protector (LATS-P), which has been detected in a large number of patients with hyperthyroidism.2 Although there have been reports of neonatal thyrotoxicosis, this report is the first to our knowledge to describe its consecutive occurrence in four siblings born to a previously thyrotoxic woman.
Report of Cases.—The mother is a 40-year-old, gravida 6, para 4, abortus 2 woman who was well until 1950 when, at the age of 16, hyperthyroidism developed and she underwent a partial thyroidectomy and a course of iodine 131 therapy. She