Genotypic and clinical spectrum of self-improving collodion ichthyosis: ALOX12B, ALOXE3, and TGM1 mutations in Scandinavian patients.

Infants born with autosomal recessive congenital ichthyosis (ARCI) are often encapsulated in a collodion membrane, which shows a lamellar or erythrodermic type of ichthyosis upon shedding. However, some babies show a nearly normal underlying skin after several weeks, a phenotype called "self-healing collodion baby" (SHCB). Mutations in two genes, TGM1 and ALOX12B, have previously been implicated in the etiology of SHCB, but the full genotypic spectrum remains to be determined. DNA sequencing in 11 Swedish and 4 Danish SHCB patients showed ALOX12B mutations in eight cases, ALOXE3 mutations in three cases, and TGM1 mutations in one case. In three patients, we could not find mutations in any of the known ARCI genes. In all cases, a spontaneous shedding of the collodion membrane occurred 2-4 weeks after birth. When re-examined at 2-37 years of age, the patients showed skin xerosis, a mild or focal scaling, palmar hyperlinearity with keratoderma, and a frequent appearance of red cheeks and anhidrosis. Thus, we propose replacing SHCB with the term "self-improving collodion ichthyosis" (SICI). In conclusion, ALOX12B mutations are the leading cause of SICI in Scandinavia, followed by ALOXE3 mutations, which have not been previously associated with this variant of ARCI.