Pituitary dwarfism represents a genetically heterogeneous group of disorders which may be classified on the basis of: associated developmental anomalies or degenerative disease; deficiency of, or peripheral insensitivity to HGH; the number of deficient hormones; the associated metabolic disturbances; and the mode of inheritance. Hereditary forms of pituitary dwarfism include: congenital absence of the pituitary, panhypopituitary dwarfism (autosomal and X-linked recessive forms), isolated HGH deficiency (Types I and II), Laron type of dwarfism, and peripheral unresponsiveness to HGH (the African Pygmies).