Harlequin-type ichthyosis is a genetic disorder that results in thickened skin over nearly the entire body at birth. The skin forms large, diamond/trapezoid/rectangle-shaped plates that are separated by deep cracks. These 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. The condition is the most severe form of ichthyosis, a group of genetic disorders characterised by scaly skin.Harlequin-type ichthyosis is caused by mutations in the ABCA12 gene. This gene codes for a protein necessary for transporting lipids out of cells in the outermost layer of skin. The disorder is autosomal recessive and inherited from parents who are carriers. 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 for the condition. Early in life, constant supportive care is typically required. Treatments may include moisturizing cream, antibiotics, etretinate or retinoids. Around half of those affected die within the first few months; however, retinoid treatment can increase chances of survival. Children who survive the first year of life often have long-term problems such as red skin, joint contractures and delayed growth. The condition affects around 1 in 300,000 births. It was first documented in a diary entry by Reverend Oliver Hart in America in 1750.
The eyes appeared to be lumps of coagulated blood, turned out, about the bigness of a plum, ghastly to behold. It had no external ears, but holes where the ears should be. The hands and feet appeared to be swollen, were cramped up and felt quite hard. The back part of the head was much open. It made a strange kind of noise, very low, which I cannot describe. It lived about forty-eight hours and was alive when I saw it." The harlequin-type designation comes from the diamond shape of the scales at birth (resembling the costume of Arlecchino). Gallery
Notable cases
Nusrit "Nelly" Shaheen (born in 1984) is possibly the oldest known survivor; she resides in Coventry, England, and was one of nine children in a Pakistani Muslim household. Four of her eight siblings also had the condition but died as young children. Ryan Gonzalez (born in 1986) is the oldest person in the United States living with the disease. He was featured in an episode of Medical Incredible. Stephanie Turner (1993 – 2017) was the second oldest person in the United States living with the disease, and the first ever to give birth. Turners two children do not have the disease. She died on March 3, 2017, at age 23. Mason van Dyk (born 2013), despite being given a life expectancy of one to five days, was five years old as of July 2018.