Hypothyroidism Caused by Chronic Autoimmune Thyroiditis in Very Young Infants

Abstract

Hypothyroidism in neonates and very young infants is usually caused by thyroid dysgenesis associated with an absent, ectopic, or hypoplastic gland1. It can be detected by neonatal screening, even if it is not clinically evident at that time. Although this condition is usually permanent, it can be transient, as it is, for example, in infants of mothers with chronic autoimmune thyroiditis2,3. In these infants transplacental passage of maternal thyrotropin-receptor antibodies inhibits the action of thyrotropin on the infant's thyroid gland until the antibodies are metabolized by the infant during the first several weeks of life2–4. . . .