ATP binding cassette subfamily A member 12
The ABCA12 gene provides instructions for making a protein known as an ATP-binding cassette (ABC) transporter. ABC transporter proteins carry many types of molecules across cell membranes. In particular, the ABCA12 protein plays a major role in transporting fats (lipids) in cells that make up the outermost layer of skin (the epidermis). This lipid transport is needed to maintain the layers of lipids within the epidermis that are necessary to prevent water loss (dehydration) and for normal development of the skin. The ABCA12 protein is also found in several other tissues, including the testes, placenta, lungs, stomach, fetal brain, and liver.
More than 65 mutations in the ABCA12 gene have been identified in people with harlequin ichthyosis. This skin condition is characterized by hard, thick scales that are present at birth; excessive dehydration; and increased risk of infections. Most of the mutations lead to an absence of ABCA12 protein or the production of an extremely small version of the protein that cannot transport lipids properly. A lack of lipid transport causes numerous problems with the development of the epidermis before and after birth. Specifically, it prevents the skin from forming an effective barrier against dehydration, and leads to the skin problems characteristic of harlequin ichthyosis.
At least 20 mutations in the ABCA12 gene have been found to cause nonbullous congenital ichthyosiform erythroderma (NBCIE). This condition affects the skin and causes redness; the development of fine, white scales; an increased risk of infections; and dehydration. These skin abnormalities tend to be less severe than those in harlequin ichthyosis (described above). Most of the mutations that cause NBCIE change single amino acids in the ABCA12 protein. These mutations likely lead to the production of a protein with reduced function, which impairs lipid transport and the formation of the lipid layers within the epidermis. Problems with this protective barrier underlie the skin abnormalities and other features of NBCIE.
Genetics Home Reference provides information about lamellar ichthyosis.
- ATP-binding cassette 12
- ATP-binding cassette transporter 12
- ATP-binding cassette, sub-family A (ABC1), member 12
- ATP-binding cassette, sub-family A, member 12