Genetic disorders of human growth.

Growth in humans is a complex process, controlled at numerous levels and by a myriad of factors. These factors may act centrally or peripherally and may be hormones, receptors, or transcription factors. Many of these probably are still unknown. The factors that are discussed here include those that act on the developing pituitary gland (transcription factors including LHX3, HESX1, PROP1, and PIT-1); those that regulate the normal activity of the pituitary (hypothalamic hormones such as GHRH, Ghrelin [growth hormone secretagoguel and somatostatin); those factors coming from the pituitary (essentially growth hormone [GH]); and the downstream modulators, transducers, and effectors of GH (including the GH receptor/GH binding protein, insulin-like growth factor-I and -II, their receptors, and their binding factors). What is becoming increasingly clear is the role of genetics in determining stature. This review discusses the most clinically relevant factors, with an emphasis on ontogeny, genetic inheritance, and clinical presentation.