- A condition in infancy or early childhood due to an in-utero deficiency of thyroid hormones that can be caused by genetic or environmental factors, such as thyroid dysgenesis or hypothyroidism in infants of mothers treated with thiouracil during pregnancy. Endemic cretinism is the result of iodine deficiency. Clinical symptoms include severe mental retardation, impaired skeletal development, short stature, and myxedema.
- A deficiency of thyroid hormone present at birth. The etiology can be genetic or environmental, or a combination of both; treatment is based on severity and causality.
- Condition due to congenital lack of thyroid hormone, marked by arrested physical and mental development, dystrophy of the bones and soft parts, and lowered basal metabolism; it is the congenital form of thyroid deficiency, while myxedema is the acquired form.