What Is the Harlequin Ichthyosis?
Harlequin ichthyosis is a severe genetic disorder that mainly affects the skin. Infants with this condition are born 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.
The skin normally forms a protective barrier between the body and its surrounding environment. The skin abnormalities associated with harlequin ichthyosis disrupt this barrier, making it more difficult for affected infants to control water loss, regulate their body temperature, and fight infections.
Infants with harlequin ichthyosis often experience an excessive loss of fluids (dehydration) and develop life-threatening infections in the first few weeks of life. It used to be very rare for affected infants to survive the newborn period. However, with intensive medical support and improved treatment, people with this disorder now have a better chance of living into childhood and adolescence.
The disease is very rare and the exact incidence is unknown. However, according to a 2014 paper written by Ahmed H and O’Toole EA, two researchers from Department of Dermatology, Barts Health National Health Service Trust, one in 3,00,000 babies get this disease.
Mutations in the ABCA12 gene cause the disease. The ABCA12 protein plays a major role in transporting fats in cells that make up the outermost layer of skin. Severe mutations in the gene lead to absence or partial production of the ABCA12 protein. This results in lack of lipid transport and as a result the skin development is affected by varying degrees according to the severity of the mutation.
For a baby to inherit this condition, both father and mother, should be carriers of the mutated ABCA12 gene. This type of inheritance is called autosomal recessive pattern.
There is no cure for the disorder but it can be managed with treatment. In the past the disease was considered fatal. But with advanced technology improved survival rate has been achieved with intense neonatal care.