Lamellar Ichthyosis Workup

Updated: Jun 28, 2017
  • Author: Chris G Adigun, MD, FAAD; Chief Editor: Dirk M Elston, MD  more...
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Workup

Approach Considerations

Genetic diagnosis and counseling of this disorder is imperative, and prenatal diagnosis for those at risk is encouraged. Genetic linkage studies have confirmed that mutations in TGM1, the gene encoding transglutaminase-1, is responsible for the development of this disorder. [10] Prenatal diagnosis is achieved through examination of the fetal skin by biopsy or amniotic fluid by electron microscopy. The expression and increased activity level of transglutaminase 1 is a key diagnostic tool. [11]

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Laboratory Studies

As a result of the abnormal skin barrier, neonatal sepsis is a significant risk in the newborn period. If sepsis is considered, perform a sepsis workup. Chemistries and fluids need to be monitored closely because of the high incidence of hypernatremia observed.

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Procedures

Skin biopsies can aid in the diagnosis of lamellar ichthyosis and detection of transglutaminase-1 expression. At birth, electron microscopy can be used to differentiate a severe collodion baby affected by lamellar ichthyosis from a baby affected by harlequin ichthyosis by demonstrating the absence of the marginal band. [16]

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Histologic Findings

Skin biopsy results show a normal or thickened granular layer, mild-to-moderate hyperkeratosis with increased mitoses, and a perivascular lymphocytic infiltrate. In autosomal dominant lamellar ichthyosis, the stratum granulosum and stratum corneum are separated by a prominent transforming zone and scales contain elevated triglyceride and fatty acid levels, which aids in differentiation from autosomal recessive lamellar ichthyosis.

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