Failure of thyroid secretion from infancy leading to dwarfism and mental retardation is included under
Failure of thyroid secretion from infancy leading to dwarfism and mental retardation is known as cretinism while in adults the deficiency of thyroid hormone causes myxoedema (gull's disease).
Patient having pituitary dwarfism due to deficiency of growth hormone does not have mental retardation.