Pseudoxanthoma elasticum (PXE) is a progressive disorder that is characterized by the accumulation of deposits of calcium and other minerals (mineralization) in elastic fibers. Elastic fibers are a component of connective tissue, which provides strength and flexibility to structures throughout the body.

Mutations in the ABCC6 gene cause PXE. This gene provides instructions for making a protein called MRP6 (also known as the ABCC6 protein). This protein is found primarily in cells of the liver and kidneys, with small amounts in other tissues, including the skin, stomach, blood vessels, and eyes. MRP6 is thought to transport certain substances across the cell membrane; however, the substances have not been identified. Some studies suggest that the MRP6 protein stimulates the release of a molecule called adenosine triphosphate (ATP) from cells through an unknown mechanism. ATP can be broken down into other molecules, including adenosine monophosphate (AMP) and pyrophosphate. Pyrophosphate helps control deposition of calcium and other minerals in the body. Other studies suggest that a substance transported by MRP6 is involved in the breakdown of ATP. This unidentified substance is thought to help prevent mineralization of tissues.

PXE affects approximately 1 in 50,000 people worldwide. For reasons that are unclear, this disorder is diagnosed twice as frequently in females as in males.

PXE is inherited in an autosomal recessive manner, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition.

Published Date: January 01, 2015
Published By: National Institutes of Health