Introduction
Harlequin fetus (Harlequin ichthyosis) is a rare, severe genetic disorder that mainly affects the skin of a newborn. It is an autosomal recessive disease that affects one in five lakh live births. The newborn infant's skin is covered with diamond-shaped plates similar to fish scales. It affects the shape of the nose, eyelids, ears, and mouth, interfering with the movement of arms and legs. In addition, thick hard plates of skin present on the face and chest cause breathing difficulties. Thus newborns with Harlequin ichthyosis need immediate neonatal care unit management. Even though the Harlequin fetus is a serious medical condition, recent advances in the field of modern medicine have made an improved response to treatment and life expectancy.
What Is a Harlequin Fetus?
Harlequin fetus is a severe form of ichthyosis with extreme skin dryness and scaling all over the body. In this condition, newborn infants are born prematurely with hard trapezoid or diamond-shaped heavy skin plates separated by deep cracks. These skin abnormalities disrupt the shape of the nose, eyelids, ears, and mouth resulting in abnormal facial features. Thickened skin over the nose and chest interferes with normal respiration and causes breathing difficulties and feeding problems. Abnormally hard skin plates in the entire body disrupt normal protective functions of the skin and result in recurrent infections, water loss, and altered body temperature. After the newborn period, the skin plates usually shed, leaving widespread redness and scales. Improved medical care and support are needed for the infants to survive the initial days and improve overall health.
What Are the Causes of a Harlequin Fetus?
Harlequin fetus (Harlequin ichthyosis) occurs due to variations (mutation) in the function of the ABCA12 gene. This gene plays a vital role in regulating protein synthesis and skin development. ABCA12 gene gives instructions to produce ABCA12 proteins that promote the transport of lipids and enzymes in the outermost skin layers, which is essential for developing normal skin cells. Any alterations in the response of the ABCA12 gene lead to abnormality in the protein and disrupted lipid transport in the skin. Altered ABCA12 protein causes abnormal development and functions of the epidermis (outer skin layer), resulting in skin abnormalities of the Harlequin fetus.
What Are the Symptoms of a Harlequin Fetus?
In the Harlequin fetus, newborns present with hard, fissured skin with hyperkeratosis. Other than skin disorders, these infants may have poor mental and physical development. Children born with Harlequin ichthyosis usually present with severe facial and cranial deformities.
Clinical symptoms present in the Harlequin fetus are the following.
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Red, scaly skin.
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Poorly developed ears.
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Everted eyelids (ectropion).
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Flat nose.
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Frequent respiratory infections.
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Swollen hands and feet.
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Inability to close eyelids.
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Low body temperature.
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Severe dry skin.
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Recurrent eye infections.
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Deformed lips.
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High sodium content in the blood.
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Nursing difficulties.
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Small hands and feet.
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Fused ears.
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Open mouth.
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Underdeveloped fingers.
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Lack of regular muscle movements.
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Thin or sparse hairs.
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Thick fingernails.
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Abnormal facial features.
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Reduced finger movements.
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Hearing problems.
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Skin infections.
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Cracked skin.
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Temperature sensitivity.
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Dehydration.
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Difficulty in breathing.
How Can We Diagnose a Harlequin Fetus?
Harlequin fetus is diagnosed based on their physical appearance during birth. Physical examination of the characteristic features of Harlequin ichthyosis (hard deep diamond skin plates) is helpful for initial diagnosis. Some laboratory tests can also be done with a physical examination to confirm the Harlequin fetus. Genetic testing accounts for the most specific test and reveals mutation and loss of function of the ABCA12 gene. In addition, histological changes associated with skin can be identified using skin biopsy. Prenatal testing for Harlequin ichthyosis can be done by testing mutations in the ABCA12 gene present in the fetal DNA (deoxyribonucleic acid). Some features associated with Harlequin ichthyosis can be seen on ultrasound radiographs during pregnancy (second trimester).
What Are the Treatment Options for Harlequin Fetus?
The Harlequin fetus is managed with the help of a multidisciplinary medical team. Immediate neonatal intensive care unit (NICU) facilities are provided to the baby after birth. After early intensive treatment, lifelong care is needed to improve the overall condition of the baby.
The steps involved in the treatment of the Harlequin fetus are the following.
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Initial Emergency Management - As soon as the baby is born with Harlequin ichthyosis, intensive care is provided to reduce complications and improve outcomes. In addition, specific management is needed for respiratory distress, feeding difficulties, dehydration, electrolyte imbalance, infections, and thermoregulation.
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Initial Treatment - Once the baby is shifted from the neonatal intensive care unit (NICU), long-term care is needed to manage their overall health. The thick skin plates will gradually peel off, leaving the inner skin layers exposed. Therefore, extensive daily care must be done to prevent skin cracks and infections. Oral retinoids can be used in severe cases to improve outcomes. Antibiotics can also be given in order to avoid skin infections and further complications. Lubricating eye drops can be used to reduce dryness and irritations. Most infants born with Harlequin ichthyosis need proper medical care for several weeks of life.
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Supportive Treatment - There is no specific treatment option for the Harlequin fetus (Harlequin ichthyosis). Long-term management includes supportive care, including reduction of skin dryness and prevention of infection. Continuous peeling off thick plates of the skin results in dry, reddened areas exposing the inner skin layers. Skin irritations and dryness can be reduced by applying moisturizers. It can be done after bathing while the skin is moist. Moisturizers containing ceramides, lanolin, petrolatum, cholesterol, and alpha hydroxy acids (AHAs) can be used to prevent skin fissures and cracks. Removal of the damaged skin plates can be done in certain areas like fingers to improve blood circulation.
Conclusion
Harlequin fetus (Harlequin ichthyosis) is a rare skin disorder characterized by severe dryness and thick skin plates all over the body. It occurs due to a genetic mutation of the ABCA12 gene, which codes for skin proteins. Infants born with Harlequin ichthyosis may develop difficulties in breathing and feeding due to the presence of hard skin plates over the nose, mouth, and chest. Even though it presents severe difficulties and symptoms, babies born with Harlequin ichthyosis are able to live up to early adulthood with intensive medical support and advanced treatment options.
