Normal Function

The COL5A1 gene provides instructions for making a component of type V collagen. Collagens are a family of proteins that strengthen and support many tissues in the body, including skin, ligaments, bones, tendons, and muscles.

A component of type V collagen called the pro-α1(V) chain is produced from the COL5A1 gene. Collagens begin as rope-like procollagen molecules that are each made up of three chains. Two combinations of chains can produce type V collagen: three pro-α1(V) chains or two pro-α1(V) chains and one pro-α2(V) chain (which is produced from the COL5A2 gene).

The triple-stranded procollagen molecules are processed by enzymes outside the cell to create mature collagen. The collagen molecules then arrange themselves into long, thin fibrils with another form of collagen, type I. Type V collagen regulates the width (diameter) of those fibrils. Studies suggest that type V collagen also controls the assembly of other types of collagen into fibrils in several tissues.

Health Conditions Related to Genetic Changes

Ehlers-Danlos syndrome

Mutations in the COL5A1 gene cause a form of Ehlers-Danlos syndrome called the classical type. Ehlers-Danlos syndrome is a group of disorders that affect the connective tissues that support the skin, bones, blood vessels, and many other organs and tissues. This form of the disorder is characterized by skin that is soft, highly stretchy (elastic), and fragile; abnormal scarring; and an unusually large range of joint movement (hypermobility). More than 100 COL5A1 gene mutations have been identified in people with classical Ehlers-Danlos syndrome. The mutations affect one copy of the gene in each cell, reducing the amount of pro-α1(V) chains that cells produce. As a result, fibrils containing type V and type I collagens in the skin and other tissues are disorganized and larger than usual. Researchers believe that the abnormal collagen weakens connective tissues throughout the body, which causes the signs and symptoms of classical Ehlers-Danlos syndrome.

Carpal tunnel syndrome

MedlinePlus Genetics provides information about Carpal tunnel syndrome

Keratoconus

MedlinePlus Genetics provides information about Keratoconus

Other Names for This Gene

• alpha 1 type V collagen preproprotein
• CO5A1_HUMAN
• collagen type V alpha 1
• collagen, type V, alpha 1

Genomic Location

Normal Function

The COL5A2 gene provides instructions for making a component of type V collagen. Collagens are a family of proteins that strengthen and support many tissues in the body, including skin, ligaments, bones, tendons, and muscles.

A component of type V collagen called the pro-α2(V) chain is produced from the COL5A2 gene. Collagens begin as rope-like procollagen molecules that are each made up of three chains. Two combinations of chains can produce type V collagen: three pro-α1(V) chains (produced from the COL5A1 gene) or two pro-α1(V) chains and one pro-α2(V) chain.

The triple-stranded procollagen molecules are processed by enzymes outside the cell to create mature collagen. The collagen molecules then arrange themselves into long, thin fibrils with another form of collagen, type I. Type V collagen regulates the width (diameter) of those fibrils. Studies suggest that type V collagen also controls the assembly of other types of collagen into fibrils in several tissues.

Health Conditions Related to Genetic Changes

Ehlers-Danlos syndrome

Mutations in the COL5A2 gene have been identified in a small number of people with a form of Ehlers-Danlos syndrome called the classical type. Ehlers-Danlos syndrome is a group of disorders that affect the connective tissues that support the skin, bones, blood vessels, and many other organs and tissues. This form of the disorder is characterized by skin that is soft, highly stretchy (elastic), and fragile; abnormal scarring; and an unusually large range of joint movement (hypermobility). About 20 COL5A2 gene mutations have been identified in people with classical Ehlers-Danlos syndrome. These mutations, which affect one copy of the gene in each cell, change the structure of the pro-α2(V) chain. As a result, fibrils containing type V and type I collagens are disorganized and larger than usual. Researchers believe that the abnormal collagen weakens connective tissues throughout the body, which causes the signs and symptoms of classical Ehlers-Danlos syndrome.

Other Names for This Gene

• AB collagen
• CO5A2_HUMAN
• collagen type V alpha 2
• collagen V, alpha-2 polypeptide
• collagen, fetal membrane, A polypeptide
• collagen, type V, alpha 2

Genomic Location

• Smooth, velvety skin that is highly elastic (stretchy) and bruises easily
• Abnormal wound healing that may result in wide, atrophic scars (flat and/or depressed scars)
• Joint hypermobility that leads to frequent dislocations and subluxations (partial dislocations)
• Molluscoid pseudotumors (calcified hematomas over pressure points such as the elbow)
• Subcutaneous spheroids (fat-containing cysts that are often found on the forearms and/or shins)
• Hypotonia
• Delayed motor development
• Tissue fragility that may lead to hernias, rectal prolapse, and other complications
• Cardiovascular abnormalities such as mitral valve prolapse or aortic root dilatation (enlargement of the blood vessel that distributes blood from the heart to the rest of the body)
• Pregnancy may be complicated by premature rupture of membranes