Harlequin ichthyosis, also called ichthyosis congenital, is a genetic disorder that mainly affects the skin of newborn babies.
Babies with this condition develop a thick, dry and scaly skin consisting of hard diamond-shaped plates separated by deep cracks.
Harlequin ichthyosis is a very rare disorder with a very few cases reported in literature. The first case was described in 1970 from South Carolina. Severe cases usually do not survive beyond a few days or weeks after birth. With the right treatment, some patients have survived into adulthood, the oldest living case having entered into her 30s.
What is the Cause of Harlequin Ichthyosis?
Harlequin ichthyosis is a genetic disorder that occurs due to a mutation in the ABCA12 gene. The gene plays an important role in the production of a protein that transports fats into the outer layer of the skin and helps in its development. Defect in the gene, therefore, does not allow the proper development of the skin, thereby explaining the appearance of the baby.
The ABCA12 gene is inherited by the baby from its parents in an autosomal recessive pattern. This means that the baby requires a pair of defective genes and should inherit one defective gene from each parent to manifest the condition. The parents may have only one defective gene each and therefore, may be apparently completely normal. If both the parents were close blood relations, the chances that both have the same defective gene are higher, which increases the chances of the baby suffering from the condition.
What are the Symptoms of Harlequin Ichthyosis?
Harlequin ichthyosis affects the skin. The baby is born with the following features:
- The skin is thick, dry and has a fish-scale pattern. It consists of thick diamond-shaped plates separated by deep cracks or fissures
- The eyes appear bulging due to the pulling back of the eyelids
- The mouth appears open due to the pulling back of the lips. Feeding may be difficult
- The outer part of the ear may be absent, making the ears look like holes
- The nose appears flat
- The movement of the limbs may be restricted. The development of the limbs may be incomplete
The lack of healthy skin results in complications, which include:
- Loss of water, resulting in dehydration
- Life-threatening infections. Infection of the blood called sepsis may occur
- Inability to regulate body temperature
- Breathing difficulties and respiratory failure due to inability of the chest to move properly
How Can You Diagnose Harlequin Ichthyosis?
Harlequin ichthyosis is diagnosed based on:
- The physical examination of the baby, which reveals the typical appearance of the skin
- Genetic testing can detect the abnormal genes and confirm the diagnosis
Diagnosis can be made even before birth.
- Fetal cells obtained through a procedure called amniocentesis or chorionic villus biopsy can be subjected to genetic tests. This test can be done early in pregnancy when a similar case was noted earlier in the family
How Can You Treat Harlequin Ichthyosis?
Harlequin ichthyosis is usually treated with supportive care. Complications should be prevented, or diagnosed and treated early. The prognosis improves once the baby survives the first few weeks.
- The baby should be kept in humidified incubator to maintain its body temperature and provide humidified air. The environment should be sterile to prevent infection till the baby’s condition stabilizes
- Adequate fluids and electrolytes should be given to prevent dehydration
- Drugs like isotretinoin have been used to facilitate healing of the skin in these patients
- Lubricants applied to the eyes protect them from damage
- The skin should be moisturized with moisturizers, and soaked for prolonged duration in water during bath
- Surgery may be required to relieve skin tightening and improve function of limbs
- Regular follow-up of the patient will help to diagnose and treat any problems arising from the condition or its treatment
Harlequin ichthyosis cannot be prevented. However, since the defective gene has to be inherited from both parents, the chances of both parents having the defective gene are higher if the parents were close blood relations before marriage. Therefore consanguineous marriages should be avoided as far as possible.
If a couple already has had a baby with harlequin ichthyosis, genetic counseling
may help the couple understand the risk of having another baby with the same condition.