Medical Megamania: Collodion Baby

Lamellar ichthyosis (LI) is an autosomal recessive disorder that is apparent at birth and is present throughout life. The newborn is born encased in a collodion membrane that sheds within 10-14 days. The shedding of the membrane reveals generalized scaling with variable redness of the skin. The scaling may be fine or platelike, resembling fish skin. Although the disorder is not life threatening, it is quite disfiguring and causes considerable psychological stress to affected patients. Ectropion will be present. There will be macroglossia.

Patients with lamellar ichthyosis have accelerated epidermal turnover with proliferative hyperkeratosis, in contrast to retention hyperkeratosis. This involves a mutation in the gene for transglutaminase 1 (TGM1). The transglutaminase 1 enzyme is involved in the formation of the cornified cell envelope. The formation of the cornified cell envelope is an essential scaffold upon which normal intercellular lipid layer formation in the stratum corneum occurs. Thus, mutations in the TGM1 secondarily cause defects in the intercellular lipid layers in the stratum corneum, leading to defective barrier function of the stratum corneum and to the ichthyotic phenotype seen in lamellar ichthyosis patients and in transglutaminase 1 knockout mice. How much a defective cornified cell envelope alone contributes to the barrier abnormality in ichthyoses remains unclear.^[1]

To date, 6 genes for lamellar ichthyosis have been localized and 5 of them identified, as follows^[2]:

TGM1 (14q11)
ABCA12 (2q34)
19p12-q12
19p13
ALOXE3-ALOX12B (17p13)
ichthyin (5q33)

In the neonatal period, following the shedding of the collodion membrane, the newborn is at risk for secondary sepsis and hypernatremic dehydration.

As the child ages, the hyperkeratosis can interfere with normal sweat gland function, which can predispose to heat intolerance and possible heat shock. Ectropion may result in the inability to fully close the eyelids and can cause exposure keratitis.

Recently , a case was reported in ESI Post Graduate Institute of Medical Sciences and Research, Rajajinagar,Bangalore.