From GHRH to IGF-1 and downstream: clinical phenotypes and biological mechanisms.

Genetic defects have been observed at almost all levels of the GHRH-IGF-1 axis. The first observations of GH-1 gene deletions date some 30 years ago. Whereas mutations in the GH-1 and GHRHR genes account for the majority of mutations detectable in patients with Isolated Growth Hormone Deficiency (IGHD) resulting in postnatal growth failure, the overall detection of genetic defects in these patients remains low with app.