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Congenital skin disease in which the skin builds up
and scales (“fish skin disease”). Associated with a very poor prognosis
(usually death if infant is younger than 1 week).
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Harlequin Fetus; Harlequin-Type Ichthyosis.
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First reported in the diary of the Reverend O. Hart in
1750. Inheritable disorder of keratinization caused by a structural defect
of tonofibrils (abnormal alpha-protein structure of keratin). This lesion is
distinct from the lamellar exfoliative type of congenital ichthyosis, the
prognosis of which is better.
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Rare (three cases per year in the United Kingdom).
Harlequin syndrome is one of the four reported genetic disorders of
keratinization displaying a structural defect of tonofibrils; the other
three are bullous (or congenital) ichthyosiform erythroderma, Curth-Macklin
form of ichthyosis hystrix, and ichthyosis hystrix gravior.
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Autosomal recessive. Chromosome 18 might carry
the gene responsible for the disorder (transglutaminase 1 [TGM1]). Prenatal
diagnosis is available (skin biopsies of the fetus).
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In the harlequin fetus, an abnormal radiographic
diffraction pattern of the horn material points to a cross-beta-protein
structure instead of the normal alpha-protein structure of keratin. A
suggested cause for this finding is an abnormality of keratinization.
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Characteristic clinical picture. Skin biopsy
demonstrating severe cornification. Mutations in TGM1 are identified by
sequence analysis of complementary DNA isolated from a fresh 2-mm skin punch
biopsy.
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Many are stillborn. Others are of low birth
weight for dates and, as a rule, die in less than 1 week as a consequence of
severe restriction of chest movement and abdomen incompatible with respiration and
feeding. Thermoregulation disorders. Plaques, measuring up to 4 or 5 cm per
side, have a diamond-like configuration resembling the suit of a harlequin
clown. One patient survived 6 years with considerable failure to thrive,
probably related to the enormous losses of protein in desquamated skin.
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In practice, because of the
severity of the disease, harlequin syndrome patients are not eligible for
surgery and anesthesia. Assess the severity of the disease, particularly
in regard to the thoracic and abdominal involvement. Limit skin desiccation
by providing continuous warm humidification of the baby. Assess nutritional
state. Exclude the presence of hypovolemia caused by poor feeding. Check core
temperature since hypothermia is often present. Investigations: hemoglobin,
arterial blood gas analysis, serum protein, and albumin levels.
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Venous access is often difficult. Strict
aseptic measures must be taken for venous cannulation because the impaired
skin barrier is predisposed to infection. Secure the venous cannulas with
petroleum jelly gauze and tie or suture down. Adhesive tape likely will
denude the skin and cause bleeding. ECG monitoring may require needle
electrodes or pads without adhesive for the same reason. Semiflexed rigid
limbs require careful positioning to prevent pressure sores. Severe
ectropion and bulging eyes require ointment and careful taping to
prevent ocular injury. Measures to maintain normothermia should be
instituted. Involvement of the chest and abdomen that interferes with
respiration ...