ABCC6

The ABCC6 gene provides instructions for making a protein called ATP-binding cassette, sub-family C, member 6. This protein is found primarily in the liver and kidneys, with small amounts in other tissues such as the skin, stomach, blood vessels, and eyes. The ABCC6 protein belongs to a group of proteins that transport molecules across cell membranes.

Little is known about the function of the ABCC6 protein or the substances it transports. This protein, or substances it transports, may play a role in the activities of connective tissue, the material that provides strength and flexibility to structures throughout the body. Some researchers suggest that substances transported by the ABCC6 protein help to regulate how much calcium is deposited in certain tissues, through a process called calcification.

pseudoxanthoma elasticum - caused by mutations in the ABCC6 gene

More than 150 ABCC6 mutations that cause pseudoxanthoma elasticum have been identified. These mutations lead to an absence of ABCC6 protein or an altered protein that does not function properly. The most common mutation in the United States, found in about 28 percent of people with pseudoxanthoma elasticum, deletes part of the ABCC6 gene. (This mutation is written as Ex23_29del.)

It is unclear how ABCC6 mutations lead to the signs and symptoms of pseudoxanthoma elasticum, particularly abnormalities in elastic fibers, which are a component of connective tissue. Within the liver and kidney, lack of functional ABCC6 protein may disrupt the transport of particular substances into the blood for distribution to other parts of the body. Without these substances, normal activities in connective tissue, such as the assembly of elastic fibers, may be impaired. Another possibility is that disrupted transport reduces levels of substances that normally inhibit calcification of elastic fibers. As a result, calcium may accumulate in elastic fibers of tissues affected by pseudoxanthoma elasticum, such as the skin.