Harlequin ichthyosis is a severe genetic disorder that affects the skin. Infants with this condition are born prematurely with very hard, thick skin covering most of their bodies. The skin forms large, diamond-shaped plates that are separated by deep cracks (fissures). These skin abnormalities affect the shape of the eyelids, nose, mouth, and ears, and limit movement of the arms and legs. Restricted movement of the chest can lead to breathing difficulties and respiratory failure in babies with harlequin ichthyosis. Affected infants also have feeding problems.

Variants (also known as mutations) in the ABCA12 gene cause harlequin ichthyosis. The ABCA12 gene provides instructions for making a protein that is essential for the normal development of skin cells. This protein plays a major role in the transport of fats (lipids) and enzymes in the outermost layer of skin (the epidermis).

Harlequin ichthyosis is very rare; its exact incidence is unknown.

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have variants. The parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but they typically do not show signs and symptoms of the condition.

Published Date: January 07, 2022
Published By: National Institutes of Health