Harlequin Ichthyosis Definition, Reason, Symptoms, Treatment & Prevention
Understanding
Harlequin ichthyosis is a term used to describe a genetic disorder that primarily affects the skin. This disorder is very rare. Another term to describe this condition is Harlequin baby syndrome, HI, ichthyosis fetalis, or Harlequin fetus type.
The skin is a barrier between the body and the outside environment. In children born with harlequin ichthyosis, there will be skin abnormalities that damage this barrier, resulting in difficulties in regulating fluid loss, regulating body temperature and fighting infection. As a result, mortality due to this condition is very high, can reach 50 percent.
Symptom
People with harlequin ichthyosis will generally have the following typical appearance:
- Skin: appears thick with large, shiny, hyperkeratotic scales. The scales are separated by deep, reddish fissures (fissures).
- Eyes: severe ectopion (protruding eyes), causing the cornea and conjunctiva to be easily traumatized.
- Ears: the ears are flat and have no retro auricular folds. The auricles may be small or even absent. Ear holes can be covered with scales.
- Lips: pulling on the lips causes the lips to gape, which can lead to difficulty eating.
- Limbs: covered with thickened skin and causes flexion contractures. Limb movement may be restricted or even absent.
- Dysregulation of body temperature: thickened skin inhibits the work of the sweat glands and heat dissipation so that heat intolerance can appear and the child experiences hyperthermia.
- Respiratory: Impaired chest expansion can cause hypoventilation, respiratory distress and respiratory failure.
- Severe dehydration may occur due to excess fluid loss.
- Nervous system: seizures may occur due to metabolic disorders.
Reason
Harlequin ichthyosis is caused by a genetic mutation, to be precise a mutation in the ABCA12 gene on chromosome 2. This gene functions to produce proteins that are important for the formation of normal skin cells.
This disorder is inherited from parents to children in an autosomal recessive manner. This means that if both parents have the ABCA12 gene mutation, then their child will be at risk of developing harlequin ichthyosis. In these circumstances, the risk of developing harlequin ichthyosis in each pregnancy is 25 percent.
If only one parent has the ABCA12 gene mutation, then it is likely that their child will be a carrier of this condition. This means carrying a mutated gene but showing no symptoms of the disease.
Diagnosis
A person with harlequin ichthyosis will generally be born with a characteristic appearance for this condition, so that it can be recognized by looking directly at it. Before the child is born, ultrasound examination, especially 3D ultrasound, may be able to recognize some of the features of harlequin ichthyosis.
These features include a large, gaping mouth, nasal aplasia (absence), abnormal limbs, protruding eyes, rudimentary ears, and particles floating in the amniotic fluid.
Currently, genetic testing is often used to confirm the presence of mutations in the ABCA12 gene. This examination can be done prenatally (before the baby is born) with chorionic villus sampling or amniocentesis.
Genetic testing can also be done after the baby is born by taking a sample of blood or cells in the inside of the mouth. This test can also be performed on individuals who are asymptomatic to determine whether they are carriers or carriers of the gene that causes harlequin ichthyosis.
Treatment
The thick scaly skin of those with harlequin ichthyosis will gradually peel off. At this time, it is important to be given antibiotics to avoid infection. In addition, etretinate can be given to help exfoliate the skin.
Once the thick scales have peeled off, the skin will appear dry, reddish, and may be covered in thin scales with sparse hairs. Symptoms on the skin can be overcome by giving skin care regularly, for example emollients to moisturize the skin.
Death from harlequin icthyosis generally occurs in the first few days after birth. Children born with this condition require intensive care. However, with advances in medical technology, it is possible for sufferers of harlequin icthyosis to survive into their teens, some even reaching their 20s.