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 in controlling somatic growth in humans and other vertebrate species has been known for many years. Through molecular cloning and other related techniques many of the components of this axis have been characterized, with the most recent additions being key transcription factors required for pituitary development and for pituitary-specific gene expression. Several of these genes have been shown to be mutated in familial and sporadic human growth deficiency syndromes, thereby validating the central roles of the encoded proteins in the endocrine pathways regulating somatic growth. The purpose of this review is to highlight these recent advances from the perspective of the molecular genetics of human growth disorders.