[Isolated GH deficiency due to inactivating mutation of GHRH receptor]

Pituitary GH secretion is controlled by hypothalamic GHRH via its own receptor. Recently, inactivating mutants of GHRH receptor were found in subjects with isolated GH deficiency. These subjects show less typical facial appearance than those with GH gene deletion or GH resistance. They respond well to GH treatment. We found a novel mutation of GHRH receptor in a Japanese boy with IGHD. The boy was with four base pair deletion in exon 12 of GHRH receptor that caused frame shift and premature stop codon resulted in a C-terminally truncated receptor formation. This novel mutation indicated the critical role of intracellular C-terminus of the GHRH receptor.