Insensitivity to growth hormone immunodeficient (Growth hormone insensitivity With immunodeficiency) - Gen STAT5B.

Insensitivity to growth hormone immunodeficient (ghee) is a disease characterized by short stature, deficiency of the effects of growth hormone in the presence of normal or elevated levels of circulating growth hormone, resistance to exogenous therapy growth hormone, and recurrent infections. The characteristics of this disease resemble those of Laron syndrome: prominent forehead, cleft nasal bridge, underdeveloped jaw, truncal obesity, micropenis, increased serum adiponectin and low IQ compared to the general population. Some individuals with insensitivity to growth hormone with respiratory difficulties manifest immunodeficiency.

This process is due to changes in the STAT5B gene, located on the long arm of chromosome 17 (17q11.2). The protein encoded by this gene is a member of the family of STAT transcription factors. This protein mediates signal transduction triggered by various cellular ligands such as IL2, IL4, CSF1, and various growth hormones. It has been shown to be involved in various biological, such as TCR signaling, apoptosis, development of the mammary gland in adults, and sexual dimorphism of hepatic gene expression processes.

They have identified several mutations in the gene STAT5B lead to insensitivity to growth hormone immunodeficient (ghee). The identified mutations consist microdeletions or insertions which alter the encoded protein. Mutations the STAT5B gene lead to a defect in the signaling system JAK / STAT ie lead to defective GH receptor, preventing binding of GH. The defect in the receptor for growth hormone deficiency reflects binding protein of growth hormone in serum (GHBP).

This disease is inherited in an autosomal recessive pattern, that is, both copies of the gene in every cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive disease have a copy of the mutated gene, but usually show no signs and symptoms of the disease.

Tests in IVAMI: in IVAMI perform detection of mutations associated with insensitivity to growth hormone immunodeficient (ghee), by complete PCR amplification of the exons of the gene STAT5B and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).