Cretinism

hypothyroidism developing in infancy or early childhood

may also result from inborn errors in metabolism (e.g., enzyme deficiencies)

If there is maternal thyroid deficiency before the development of the fetal thyroid gland, mental retardation is severe.

impaired development of the skeletal system and central nervous system, with severe mental retardation, short stature, coarse facial features, a protruding tongue, and umbilical hernia