cretinism (krēˈtənĭzˌəm) [key], condition produced in infants and children due to lack of thyroid hormone. It usually results from a congenital defect (e.g., absence of the thyroid, presence of only a rudimentary gland, inability of the gland to produce thyroxine). However, it can develop later if there is a lack of iodine in the diet, or if the thyroid is diseased or surgically removed. Cretinism causes very serious retardation of physical and mental development; if the condition is left untreated, growth is stunted and the physical stature attained is that of a dwarf. In addition, the skin is thick, flabby, and waxy in color, the nose is flattened, the abdomen protrudes, and there is a general slowness of movement and speech. If discovered early enough and treated with thyroid extract and sufficient iodine intake throughout life, growth may become normal and mental facility greatly improved. If the condition commences after adulthood is reached it is called myxedema.