Why do babies with harlequin ichthyosis have red eyes?


What is harlequin ichthyosis?

Ichthyosis is a group of genetic skin disorders that causes thick, dry skin throughout the body. There are many types of inherited ichthyosis such as ichthyosis vulgaris, X-linked ichthyosis and others. Harlequin ichthyosis is one of the rare forms, with an overall incidence of 1 in 300,000 births. It is also the most severe form among the disorders. It is caused by a defect in the ABCA12 gene, which encodes instructions to make a particular protein that is necessary for normal skin cells. This protein plays a key role in transporting fats (lipids) to the most outermost layer of the skin (epidermis), creating an effective skin barrier. When this gene is mutated, the skin barrier is disrupted, resulting in a thick and dry skin. Harlequin ichthyosis is inherited in an autosomal recessive pattern. This means the child requires two copies of the mutated genes to manifest the disease, one from each of the parents. Hence there is a 25% chance a child can inherit the disease, and the risk is the same for males and females.

On the other hand, acquired ichthyosis started during adulthood. Patients are not born with the disease. Acquired ichthyosis is often associated with malignancies, infections, metabolic disorders and medications. Acquired ichthyosis treatment usually includes alpha-hydroxy acid lotions to hydrate the skin or topical retinoid cream.

Why do babies with harlequin ichthyosis have red eyes?

Babies born with harlequin ichthyosis have thick armor-like scales covering over the entire body. The thick tightening skin over the chest and abdomen makes it very difficult for them to breathe and eat. The hands and feet are swollen and tight. They also have abnormal facial features, such as ectropion and eclabium (eversion of the eyelids and lips), as well as flattening of the ears and nose. Babies with this disease are often mistaken for having “red eyes”. The skin around their eyes is so dry and tight that it “pulls” the eyelids to turn inside out, revealing the red inner linings. This is the same for the eversion of the lips. The inability to close the eyelids can cause drying of the eyes and potentially damage the cornea. Some may have hearing problems due to the thick skin building over the ears.

Can this disease be diagnosed before birth?

Yes. Prenatal testing is possible by testing fetal DNA for the mutated ABCA12 gene. Moreover, some features of harlequin ichthyosis may even be seen during the second trimester onward. Otherwise, harlequin ichthyosis is diagnosed at birth based on the newborn’s clinical appearance and is confirmed by genetic testing.

Can babies with harlequin ichthyosis live a normal life?

In the past, most newborns with this disease did not survive past the first few days of life. They commonly die from respiratory distress, infection or feeding problems. However, with advances in intensive neonatal and medical care, they can survive. The introduction of oral retinoids as an early treatment has increased the survival rate up to 80%. Several surviving children with harlequin ichthyosis are now young adults, some in their twenties. The survivors have dry, red skin covered by large thin scales and sparse hair. Although they experienced delayed physical development due to high caloric demands by the abnormal skin functions, these children have normal mental and intellectual capacities. However, individuals may have psychological impacts as they struggle to cope with their appearances and social stigma.

Can harlequin ichthyosis be cured?

There is no cure, but with early treatment and supportive care, patients stand a chance to live a quality life. Treatment and intensive neonatal care is started as soon as the babies are born. Due to severe skin conditions, infants with this disease often develop severe complications such as respiratory distress, dehydration, electrolyte imbalance, low body temperatures, infections and feeding difficulties. Hence, intubation, hydration, feeding tubes and warmer are often required. Lubrication is also needed to protect the cornea from drying due to ectropion. Early administration of oral retinoids greatly improves the survival rate by helping skin cells to grow normally. Gradually, the thick armor-like skin split and peel off over a few weeks, leaving the skin dry, red and scaly. At this time, antibiotic treatment may be necessary to prevent infection. Individuals can opt for skin repair formulas containing ceramides or cholesterol, moisturisers with petrolatum or lanolin, or keratolytics with alpha-hydroxy acids to keep the skin pliable and moisturised, preventing cracking that can lead to infection. It is also recommended to apply skin softening emollients after bathing to keep skin moist. Constricting bands of skin on fingers should be removed from time to time to avoid loss of blood circulation.

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