[Severe neonatal hyperthyroidism which reveals a maternal Graves' disease]

Two of every thousand pregnancies are complicated by Graves' disease. Diagnosis is suggested by maternal disorders (tachycardia, exophthalmia, weight loss.) or fetal disorders (tachycardia, intra-uterine growth retardation, preterm birth.). Due to transfer into the fetal compartment of maternal antibodies which stimulate the fetal thyroid by binding to the thyroid thyrotropin (TSH) receptor, only 1% of children born to these mothers are described as having hyperthyroidism. Neonatal thyrotoxicosis disappears with clearance of the maternal antibodies; clinical signs usually disappear during the first four Months of life. The most frequent neonatal clinical signs of thyrotoxicosis are tachycardia, goiter, hyperexcitability, poor weight gain, hepatosplenomegaly, stare and eyelid retraction. Diagnosis is based on determination of the blood level of triiodothyronine (T3), thyroxine (T4) and TSH. To confirm the nature of hyperthyroidism, thyroid-stimulating immunoglobulins (TSI) should be assayed. The kinetics of TSI provides a guide for therapeutic adaptation and disappearance of TSI is a sign of recovery. Rare cases of familial non-autoimmune hyperthyroidism have been shown to be caused by germline mutation of the thyrotropin receptor. We report a case of severe neonatal hyperthyroidism which led to the diagnosis of maternal Graves' disease.