Relations phenotype-genotype dans l'insensibilite a l'hormone de croissance

Growth hormone (GH) insensitivity is associated with several different mutations of the GH receptor gene and a recently described new genetic disorder of the IFGI gene. The phenotype and biochemical characteristics were studied in 82 patients with growth hormone insensitivity, from 23 different countries, with a mean age of 8.25 years. Mean height SDS was -6.09. SDS of the IGF binding protein -3 (IGF BP3) was 7.99. Twenty three per cent of the patients were GH binding protein (GHBP) positive (>10%). Mean height SDS score was -6.5 in the GHBP negative patients and -4.9 in the GHBP positive patients (p < 0.001). Fifteen different mutations of the GH receptor gene were identified in 27 patients. There were no relationships between the type of mutation or the involved GH receptor gene exon and height or IGFBP-3 SDS. The new phenotype due to a partial deletion of the IGFI gene was described in a 15-year-old boy who presented with a severe intrauterine growth retardation, a very poor postnatal statural growth, a neurosensorial deafness and a mild mental retardation. He had elevated GH levels, normal levels of IGFBP3, undetectable levels of IGFI, and showed no response to GH treatment. A partial deletion concerning the exons 4 and 5 of the IGFI gene was found. Thus, GH insensivity is associated with large variations in the clinical and biochemical phenotypes.