Human growth disorders: molecular genetics of the growth hormone-insulin-like growth factor I axis

The critical role of the growth hormone-insulin-like growth factor I axis i n controlling somatic growth in humans and other vertebrate species has bee n known for many years. Through molecular cloning and other related techniq ues many of the components of this axis have been characterized, with the m ost recent additions being key transcription factors required for pituitary development and for pituitary-specific gene expression. Several of these g enes have been shown to be mutated in familial and sporadic human growth de ficiency syndromes, thereby validating the central roles of the encoded pro teins in the endocrine pathways regulating somatic growth. The purpose of t his review is to highlight these recent advances from the perspective of th e molecular genetics of human growth disorders.