jaundice, thrombocytopenia, and mildly elevated hemoglobin level. However, it was interesting to speculate whether these findings were due to the hypermetabolic state per se or whether LATS may have had effects other than that of stimulating the thyroid gland.The presence of LATS in the mother might have been inferred from her physical examination find¬ ings. Recurrent hyperthyroidism, severe exophthal¬ mos, and pretibial myxedema have been associated with assay results which were positive for LATS.15 In fact, all patients with pretibial myxedema who have been studied had assay results which were positive for LATS. The presence of clubbing in the mother was of interest and raised the question of whether or not she had thyroid acropachy, which is another condition associated with elevated LATS.There was no evidence of soft tissue swelling or periosteal new bone formation in the hands, and whether clubbing alone is sufficient to make this diagnosis has not been established. Summary A patient with exophthalmos, pretibial myxe¬ dema, and thyrotoxicosis (which had recurred after a subtotal thyroidectomy) gave birth to a child with neonatal thyrotoxicosis. Both the mother and child had assay results which were positive for long-acting thyroid stimulator (LATS). In addi¬ tion to goiter and exophthalmos, the child had congestive heart failure, hepatosplenomegaly, jaun¬ dice, and thrombocytopenia. Histological examina¬ tion of the infant's thyroid gland at 3 months of age revealed hyperplasia with colloid vacuolation and papillary infolding of the follicles.