[5] ABCA12 belongs to a group of genes called the ATP-binding cassette family, which makes proteins that transport molecules across cell membranes.

The ABCA12 gene is active in some types of skin cells and in several other tissues, such as testis, placenta, lung, stomach, and fetal brain and liver.

This protein appears to be essential for normal development of the skin, which provides a barrier between the body and its surrounding environment.

Abnormalities in lipid transport prevent the skin from forming an effective barrier and result in the hard, thick scales characteristic of harlequin ichthyosis.

Changes in the structure of the ABCA12 protein likely disrupt its ability to transport lipids, which affects the development of skin before and after birth.