What causes Harlequin baby syndrome


Harlequin baby syndrome or its other name, Harlequin ichthyosis is a severe genetic disorder and a very rare disease. It mainly affects the skin where the skin forms large, diamond-shaped plates that are separated by fissures. The skin that covers most of their bodies is very thick and hard which leads to abnormalities at the shape of the eyelids, nose, mouth and ears.

The distort facial features are due to the tightness thick skin pulls around the eyes and the mouth, forcing the eyelids and lips to turn inside out, then revealing the red inner linings. Other than that, harlequin ichthyosis causes limitation of movement of part of the body. The tightness of the skin also could be the cause of restriction of chest movement. Breathing difficulties and respiratory failure can result from it.

While hands and feet may be small, swollen, and partially flexed, then restrict its movement. Eating also could be difficult due to the abdomen of the infant may be severely restricted. The ears are really fused to the head by the thick skin and the infant may appear to have no ears. This disease can be life-threatening and it used to be very rare for affected infants to survive the newborn period due to dehydration and infections.

The skin normally functions as a protective barrier that prevents excessive water loss. The skin abnormalities in patients with harlequin ichthyosis affect this barrier and cause the body difficult to regulate body temperature due to excessive loss of fluids. Thus, dehydration makes the body unable to fight infection properly. This could be fatal for the first few weeks of an infant’s life if they are not cared for in the neonatal intensive care unit immediately.

Treatment of infants with this disease is not easy. These infants are already at risk of the complication from early delivery since premature birth is typical. They added up the risk with difficulty in monitoring because of the abnormal skin. Electrides cannot be placed effectively to monitor vital signs, Blood vessels cannot be seen under the skin to place lines to deliver fluids and nutritions. They may need tube feeding as well due to constriction and swelling of the mouth that interfere with the suck response.

Maintaining normal levels of electrolytes, especially sodium may be a great problem and prone to develop hypernatremia which is high sodium levels in the blood. However, with intensive medical support and improved treatment, the patients could go through this critical time and live into their childhood. Monitoring the electrolytes can be done by placing lines in the artery and vein of the umbilical cord.

Before this happens, this disease can be detected before birth. Advanced medical technology has introduced amniocentesis or chorionic villus sampling to obtain samples of fetal DNA for genetic testing. Harlequin ichthyosis is actually caused by mutations in the ABCA12 gene which provides instructions for making a protein that is essential for the normal development of skin cells.

The genetic testing can give us information about this mutation. The ABCA12 protein plays a major role in the transport of fats (lipids) in the outermost layer of skin (the epidermis). Hence, mutations in the ABCA12 gene will disrupt the normal development of the epidermis, resulting in the hard, thick scales characteristic of harlequin ichthyosis.

This kind of genetic disorder is inherited in an autosomal recessive pattern, which means individuals must inherit two recessive genes in order to show the disease. The parents of the patient with this condition each carry one copy of the mutated gene, but the parents typically show no signs of the ichthyosis. It is called a carrier.