What is "harlequin-type ichthyosis"?

Harlequin-type ichthyosis is a genetic disorder which results in thickened skin over nearly the entire body at birth. The skin forms large, diamond-shaped plates that are separated by deep cracks. They 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. These plates fall off over several weeks. Other complications can include premature birth, infection, problems with body temperature, and dehydration.

Harlequin-type ichthyosis is due to mutations of the ABCA12 genes. It is autosomal recessive, and inherited from a person's parents. Diagnosis is often based on appearance at birth and confirmed by genetic testing. Before birth amniocentesis or ultrasound may support the diagnosis.

There is no cure. Early in life constant supportive care is typically required. Treatments may include moisturizing cream, antibiotics, etretinate, or retinoids. It affects about 1 per 300,000 births. There is no difference in rate of occurrence between sexes. Long-term problems are common. Death in the first month is relatively common. The condition was first documented in 1750.