EFEMP2

The EFEMP2 gene provides instructions for making a protein called EGF-containing fibulin-like extracellular matrix protein 2, which is also known as fibulin-4. This protein is part of a group of proteins called fibulins. Fibulins have a variety of functions in the extracellular matrix, which is the intricate lattice of proteins and other molecules that forms in the spaces between cells.

Little is known about the function of fibulin-4 in the extracellular matrix. It appears to play a critical role in the assembly of elastic fibers, which are slender bundles of protein that provide strength and flexibility to connective tissue (tissue that supports the body's joints and organs). Fibulin-4 is found in tissues and organs that are rich in elastic fibers, including the blood vessels, heart valves, lungs, and skin.

cutis laxa - caused by mutations in the EFEMP2 gene

At least three mutations in the EFEMP2 gene have been identified in people with cutis laxa. EFEMP2 mutations cause a form of the disorder called autosomal recessive cutis laxa type I, which is characterized by loose and sagging skin, a lung disease called emphysema, and severe abnormalities involving the heart and blood vessels.

Mutations in the EFEMP2 gene likely prevent cells from producing any functional fibulin-4. Without this protein, elastic fibers cannot be assembled normally in the extracellular matrix. A shortage of normal elastic fibers weakens connective tissue in the skin, blood vessels, lungs, and other organs. These defects in connective tissue underlie the major features of cutis laxa.