This gene encodes the pro-alpha2 chain of type I collagen whose triple helix comprises two alpha1 chains and one alpha2 chain. Type I is a fibril-forming collagen found in most connective tissues and is abundant in bone, cornea, dermis and tendon. Mutations in this gene are associated with osteogenesis imperfecta types I-IV, Ehlers-Danlos syndrome type VIIB, recessive Ehlers-Danlos syndrome Classical type, idiopathic osteoporosis, and atypical Marfan syndrome. Symptoms associated with mutations in this gene, however, tend to be less severe than mutations in the gene for the alpha1 chain of type I collagen (COL1A1) reflecting the different role of alpha2 chains in matrix integrity. Three transcripts, resulting from the use of alternate polyadenylation signals, have been identified for this gene. [provided by R. Dalgleish, Feb 2008]

COL1A2: Type I collagen is a member of group I collagen (fibrillar forming collagen). Defects in COL1A2 are the cause of Ehlers-Danlos syndrome type 7B (EDS7B). EDS is a connective tissue disorder characterized by hyperextensible skin, atrophic cutaneous scars due to tissue fragility and joint hyperlaxity. EDS7B is marked by bilateral congenital hip dislocation, hyperlaxity of the joints, and recurrent partial dislocations. Defects in COL1A2 are a cause of osteogenesis imperfecta type 1 (OI1). A dominantly inherited connective tissue disorder characterized by bone fragility and blue sclerae. Osteogenesis imperfecta type 1 is non-deforming with normal height or mild short stature, and no dentinogenesis imperfecta. Defects in COL1A2 are a cause of osteogenesis imperfecta type 2 (OI2); also known as osteogenesis imperfecta congenita (OIC) or lethal perinatal. A connective tissue disorder characterized by bone fragility, with many perinatal fractures, severe bowing of long bones, undermineralization, and death in the perinatal period due to respiratory insufficiency. Defects in COL1A2 are the cause of Ehlers-Danlos syndrome autosomal recessive cardiac valvular form (EDSCV). A connective tissue disorder characterized by hyperextensible skin, atrophic cutaneous scars due to tissue fragility and joint hyperlaxity. In addition to joint laxity, skin hyperextensibility and friability, and abnormal scar formation, patients have mitral valve prolapse and insufficiency, mitral regurgitation, and aortic insufficiency. Defects in COL1A2 are a cause of osteogenesis imperfecta type 3 (OI3). A connective tissue disorder characterized by progressively deforming bones, very short stature, a triangular face, severe scoliosis, grayish sclera, and dentinogenesis imperfecta. Defects in COL1A2 are a cause of osteogenesis imperfecta type 4 (OI4); also known as osteogenesis imperfecta with normal sclerae. A connective tissue disorder characterized by moderately short stature, mild to moderate scoliosis, grayish or white sclera and dentinogenesis imperfecta. A chromosomal aberration involving COL1A2 may be a cause of lipoblastomas, which are benign tumors resulting from transformation of adipocytes, usually diagnosed in children. Translocation t(7;8)(p22;q13) with PLAG1. Belongs to the fibrillar collagen family.

Protein type: Secreted, signal peptide; Secreted

Chromosomal Location of Human Ortholog: 7q22.1

Cellular Component: extracellular matrix; extracellular space; endoplasmic reticulum lumen; extracellular region; collagen type I

Molecular Function: protein binding, bridging; identical protein binding; protein binding; platelet-derived growth factor binding; extracellular matrix structural constituent; metal ion binding; SMAD binding

Biological Process: receptor-mediated endocytosis; platelet activation; blood vessel development; extracellular matrix organization and biogenesis; collagen fibril organization; skin morphogenesis; Rho protein signal transduction; odontogenesis; extracellular matrix disassembly; collagen catabolic process; transforming growth factor beta receptor signaling pathway; regulation of blood pressure; blood coagulation; skeletal development; leukocyte migration

Disease: Ehlers-danlos Syndrome, Type Vii, Autosomal Dominant; Ehlers-danlos Syndrome, Autosomal Recessive, Cardiac Valvular Form; Osteogenesis Imperfecta, Type Ii; Osteogenesis Imperfecta, Type Iii; Osteoporosis; Osteogenesis Imperfecta, Type Iv