Harlequin-type Ichthyosis


Nature of the Genetic Difficulty

Harlequin Ichthyosis is caused by mutations in the ABCA12 gene. The ABCA12 provides the coding for making a protein that is critical for the normal development of skin cells. This protein plays a major role in the transports of lipids (fats) to the outermost layer of the skin (the epidermis). Some mutations of this gene prevent
skin cells from producing the ABCA12 at all. Other mutations lead to the production of an abnormally small version of the protein, meaning the body is unable to transport lipids to the skin properly. The loss of a functional version of this protein in the body leads to the disruption of the normal development of the epidermis, resulting in the hard, thick scales typical of this genetic disorder.

Basis Facts of Disease

This disorder causes the skin to harden and thicken; because of this the skin doesn't cover the entire body. This causes the formation of deep fissures and scale-like patches of skin. The severity of the disorder differs from patient to patient, some allow for much of the patients to retain some of their motor function and immune system operation. For more extreme cases, the eye lids can be fused shut or open, there will be no motor function, very limited immune system function, and possible respiratory failure. Due to the tightness and slow shedding of the skin the patient's limbs and growth are often stunted. In addition to this, newborns born with the is almost always premature and will suffer from the problems related with premature birth.

If a patient lives past infancy, they will suffer from excessive amounts of water loss; meaning they are forced to constantly intake fluids in order to prevent extreme dehydration. Patients will also lose approximately 1,000 calories per day due to heat loss, resulting in the need for increased food consumption. Social interactions may sometimes be hampered due to the distorted facial features of the patient. Breathing and eating may sometimes be impaired, and daily treatment is necessary to prevent the dead skin cells from building up, drying, and cracking. The patient will also have to deal with compromised immune system.


Most patients die before their first birthday or in the first weeks of life. The most common cause of death for a newborn with this disease is infection due to the lack of a properly formed epidermis. Respiratory failure is also a leading cause of death as the skin doesn’t allow for sufficient room to breath. But due to recent advances in medicine, some patients have been able to survive into adulthood. Through their lifetime the patients will have to have a high calorie (feeding tube may be necessary) diet, daily doses of isotretinoin, and daily usage of lotion to prevent the skin from cracking.

Sources Cited

"Harlequin Ichthyosis." - Genetics Home Reference. U.S. National Library of Medicine, 5 Mar. 2012. Web. 11 Mar. 2012. <http://ghr.nlm.nih.gov/condition/harlequin-ichthyosis>

"Harlequin Type Ichthyosis." Dermatology. Web. 11 Mar. 2012. <http://www.lumrix.net/medical/dermatology/harlequin_type_ichthyosis.html>.