Defects in growth hormone receptor signaling.

Severe growth failure and insulin-like growth factor (IGF) deficiency were first reported 40 years ago in patients who ultimately proved to have mutations in the gene encoding the growth hormone receptor (GHR). So far, over 250 similar patients, encompassing more than 60 different mutations of GHR, have been reported. The GHR is a member of the cytokine receptor superfamily and has been shown to signal, at least in part, through the Janus-family tyrosine kinase-signal transducer and activator of transcription (JAK-STAT) pathway.