Harlequin Ichthyosis

Other names: Harlequin fetus
 
OMIM: 242500

Inheritance: autosomal recessive

Incidence: very rare
 
Physicians or NICU staff seeking to confirm a harlequin ichthyosis diagnosis, or who wish to consult with experts who have previously treated harlequin infants should submit the case to FIRST's Tele-Ichthyosis website.


Thank you for your interest in harlequin ichthyosis.   Harlequin ichthyosis is an extremely rare form of ichthyosis and is the most severe. 

Newborn children affected with harlequin ichthyosis are covered with plates of thick skin that crack and split apart.  The thick skin plates can pull at and distort the infant's facial features.  The tightness of the skin pulls around the eyes and mouth, forcing the eyelids and lips to turn inside out, revealing the red inner linings.  The chest and abdomen of the infant may be severely restricted by the tightness of the skin, making eating and breathing difficult.  The hands and feet may be small, swollen, and partially flexed.  The ears may appear to be misshapen or missing, but are really fused to the head by the thick skin.  Harlequin infants need to be cared for in the neonatal intensive care unit immediately.
In harlequin infants, premature birth is typical, leaving infants at risk for additional complications from early delivery.  These infants are also at high risk for difficultybreathing, infection, low body temperature, and dehydration.  Constriction and swelling of the mouth may interfere with the suck response and infants may need tube feeding.  Medical monitoring is difficult because of the abnormal skin; electrodes cannot be placed effectively and blood vessels cannot be seen under the skin. Placing lines in the artery and vein of the umbilical cord can aid in monitoring the infant and delivering fluids and nutrition.
Representative of harlequin appearance following the neonatal period.
These infants may have problems maintaining normallevels of electrolytes, especially sodium in their blood.  They are particularly prone to develop hypernatremia (high sodium levels in the blood).  The baby's corneas need to be lubricated and protected if the eyelids are forced open by the tightness of the skin.  A high humidity environment in a heated incubator is necessary to help maintain body temperature and to prevent the skin from cracking.

The thick plate-like skin will gradually split and peel off.  Antibiotic treatment may be necessary to prevent infection at this time.  Administration of a retinoid such as oral etretinate1 (1 mg./kg. body weight) may accelerate shedding of the thick scales.  Most harlequin infants will need one-on-one nursing care for the first several weeks of life.

In the past, harlequin infants rarely survived the first few days of life.  However, with recent advances in neonatal care and perhaps with the administration of etretinate,1 harlequin infants can survive.  Several surviving children with harlequin ichthyosis are now young adults.  The surviving children display dry, reddened skin, which may be covered by large thin scales, and sparse hair.  Physical development may be delayed by the enormous calorie needs their skin function demands, but their mental and intellectual developments are expected to be normal.  Harlequin ichthyosis demands a meticulous ongoing skin care regimen to keep the skin moisturized and pliable and to prevent cracking and fissuring that may lead to infection.

Harlequin ichthyosis is a recessively inherited genetic disorder.  In order to express (show) the disorder, individuals must inherit two recessive genes, one from each parent, but the parents (the "carriers") show no signs.  For more information regarding the genetics of harlequin ichthyosis, refer to FIRST's publication, Ichthyosis: The Genetics of its Inheritance.

Recently, in 2005, the cause of harlequin ichthyosis was traced to the ABCA12 gene.   The ABCA12 gene is believed to encode a transporter protein involved in the transport of epidermal lipids across cell membranes.  Identification of this gene has made DNA-based prenatal diagnosis of harlequin ichthyosis possible.

FIRST directs and funds research to develop better treatments and eventual cures for all types of ichthyosis, including harlequin ichthyosis.  FIRST also provides support and resources for those touched by ichthyosis.  If you are interested in supporting FIRST in its mission to provide better treatments for harlequin ichthyosis, please consider donating to FIRST.

1 It takes a week or two for etretinate to work loosening the scales.  Because most of the fatalities from this condition occur in the first few days of life, many of the successes attributed to etretinate use in the medical literature may be equally due to the high quality of care in the immediate newborn period and to a less severely affected newborn.  Unfortunately, because of the severity of their condition, some newborns with harlequin ichthyosis will not survive, even with the best of care.
   
     
Meet Brenna   Meet Evan   Meet Lauren  

In May 2013 a 20-year-old woman affected with harlequin ichthyosis gave birth to a healthy baby boy.

Read about one family's experience in the first days of the birth of their daughter affected with harlequin ichthyosis.

Learn more about FIRST's Regional Support Network -  connecting affected individuals and families with each other.

Clinicians seeking diagnosis should visit FIRST's TeleIchthyosis site to submit a case to experts in ichthyosis



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