Acromesomelic dysplasia , Maroteaux type (A cromesomelic dysplasia, Maroteaux type) - Gen NPR2.
The acromesomelic type Maroteaux dysplasia is a rare osteochondrodysplasia belonging to the group of acromesomelic dysplasias. This disease is characterized by a marked shortening dwarfism middle and distal parts of the extremities, fingers short and wide, shortened long bones of the middle segments with an arcuate radius and vertebral anomalies. Some people affected have brachydactyly. Generally, this disease does not affect facial appearance or intelligence.
The Acromesomelic dysplasia , Maroteaux type is due to mutations in the gene NPR2, located on the short arm of chromosome 9 (9p21-p12). This gene, involved in regulation of skeletal growth, encoding the receptor B natriuretic peptide, one of two integral membrane receptors of natriuretic peptides. Both NPR1 as NPR2 contain five functional domains: an extracellular binding domain ligand, a unique region spanning the membrane, and intracellularly domain protein kinase homology, a helical hinge region involved in oligomerization, and a catalytic domain adenylate cyclase carboxyl terminus. Protein is the primary receptor for the C - type natriuretic peptide (CNP), which greatly increases adenylate cyclase activity.
It has identified a total of 21 mutations in the gene NPR2 in people with Acromesomelic dysplasia , Maroteaux type. Many of them have been identified as nonsense mutations. A mutation in exon 1 of the gene NPR2 (c.494delG) causes a deletion of a nucleotide, the first amino acid Arg165 the affected. This mutation results in a truncated receptor natriuretic peptide 244 amino acids of the intracellular affects, and extracellular domains of transmembrane same.
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 Acromesomelic dysplasia , Maroteaux type, by complete PCR amplification of the exons of the gene NPR2, 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).