Prediction and therapy of intrauterine and late-onset neonatal hyperthyroidism.

TLDR: The effects of multiple antibodies directed against the TSH receptor that influenced thyroid function in the fetus and infant and combined clinical and assay data are compatible with the following interpretations.

Abstract: These studies in a mother and child describe the effects of multiple antibodies directed against the TSH receptor that influenced thyroid function in the fetus and infant. Blood was taken periodically for 6 months from a child (C3) whose mother (M) was known to have in her serum immunoglobulin G (IgG) that contained thyroid-stimulating antibody (TSAb), an inhibitor of TSAb and TSH binding and action, and an enhancer of TSH binding to its receptor, the last activity presumed to enhance both TSH and TSAb action. We correctly predicted that C3 and an older sibling, C2, would have delayed onset of hyperthyroidism (∼45 days of age) due to interaction of these antibodies. In addition, in both C2 and C3, fetal hyperthyroidism in the second trimester was postulated, and therefore, M was given propylthiouracil from then until term (C2) or 8 months (C3), with associated return of the fetal heart rate to normal in the one fetus (C3) in whom this was monitored. IgG was purified from C3's serum samples and tested for ...