Harlequin Fetus Health Article

Diagnosis

A diagnosis of HF is possible based on clinical examination after birth. However, in order to confirm a diagnosis of this particular type of ichthyosis, a skin biopsy is strongly recommended. A sample of skin is submitted for electron microscopy. This specific type of technical examination can identify the characteristic changes within the epidermal cells associated with hyperkeratosis, or overgrowth of the stratum corneum. The cells of the stratum corneum contain protein, keratin, and act as a protective barrier along the surface of the body. The process by which new epidermal cells are formed and gradually changed into the cells of the stratum corneum is referred to as keratinization. It is controlled by a number of different metabolic pathways, and an abnormality at any point can theoretically lead to conditions such as ichthyosis or other serious skin abnormalities.

Prenatal diagnosis of harlequin ichthyosis has been accomplished by biopsy of the fetal skin and microscopic analysis of cells from a sample of amniotic fluid. This is usually accomplished by a combination of fetoscopy and amniocentesis. The cellular changes associated with hyperkeratosis begin during the latter part of the second trimester of pregnancy. Prenatal diagnosis of HF has been achieved usually around 21-23 weeks gestation. In 1999, a Japanese group was able to successfully diagnosis HF at the earlier gestational age of 19 weeks in an at-risk family.

Realistically, prenatal diagnosis for HF is available only to those couples that have already had at least one affected child. Based on that family history, the parents will be carriers of a gene for HF and thus at 25% risk of having another affected child. Since a gene for HF has not been identified, carrier testing in the general population is not possible. Also, prenatal ultrasound alone will not detect many of the features associated with HF, particularly in a low-risk patient population.

Treatment and management

Infants with HF have a tendency to be born prematurely. Thus, if a prenatal diagnosis of HF has been made, and the family wishes to continue the pregnancy, the woman and her doctor can devise a plan for more intensive monitoring of the remainder of her pregnancy.

Immediate care of a newborn with HF must focus on the following: temperature control, as well as prevention of dehydration, malnutrition, and infection. Infants who are born prematurely may also have breathing problems requiring placement of a breathing tube.

In 1998, guidelines were published for the care of any newborn with a severe form of congenital ichthyosis, including HF:

• The infant should be placed in a humidified incubator immediately after delivery. Antibiotics should be administered via an intravenous (IV) line as a safeguard against infection. An IV should also be used to provide water and nutrients until the infant can suck sufficiently.
• Medication for pain management should be provided, as needed.
• Sponge baths or tub soaking and the application of skin moisturizers with antibiotics should be performed twice a day to soften the skin and reduce scaliness.
• Creams or ointments containing the drug etretinate should be used to decrease the amount of scale. Etreti-nate has been a successful mode of treatment for some infants with HF, although treated infants still died at relatively young ages due to complications from their disorder. Careful monitoring for etretinate-related side effects in children, such as bone toxicity, is recommended.
• Artifical tear treatments for infants with severe ectropion.

Prognosis

Most infants with harlequin fetus ichthyosis die within the first few days to weeks of life. Common causes of death include respiratory complications because of prematurity or constriction by the thick scale, dehydration, malnutrition, or severe skin infection. Longer-term survivors have been reported but these children have required intensive, on-going medical care. Etreti-nate has been an effective form of treatment for some infants but its use has only been for short periods of time since the affected infants have still died. Even with treatment, the ichthyosis does not completely go away. However, over time, the eversion of eyelids and lips gradually resolves. Large, thin scales with reddish edges gradually replace the cracked, thick skin. Variable neurological impairment has been reported among survivors, and, even with attentive medical care, sudden death may still occur.

BOOKS

Baden, Howard P. "Ichthyosiform Dermatoses." Emery and Rimoin's Principles and Practice of Medical Genetics. Edited by David L. Rimoin, J. Micheal Connor, and Reed E. Pyeritz. 3rd ed. St. Louis, MO: Churchill Livingstone, 1997, pp.1205-1214.

"Disorders of Keratinization." Nelson's Textbook of Pediatrics. Edited by Richard E. Behrman, Robert M. Kliegman, and Hal B. Jenson. 16th ed. Philadelphia: W. B. Saunders, 2000, p. 2007.