Lefevre et al. (2004) identified a gene for a new form of non-syndromic autosomal recessive congenital ichthyosis (ARCI) and studied its genomic localization by homozygosity mapping. The study included 11 patients (six males and five females) with ARCI from eight consanguineous Algerian families. Some patients were born as collodion babies. Seven patients presented the nonbullous congenital ichthyosiform erythroderma (NCIE) phenotype. Those patients had generalized ichthyosis with erythema, fine whitish scaling on the face and trunk, and larger brownish scaling on the neck, buttocks and legs. All patients had palmoplanter keratoderma, often yellowish with fissures, and some had clubbing of nails. Lefevre et al. (2004) identified a new gene in those patients (ichthyin). Sequencing of ichthyin gene showed four different homozygous mutations in the patients. One of these mutations was a nonsense mutation presented in three families (247C->T). The other three were missense mutations (341C->A, 437C->T, 239G->T). The product of ichthyin is predicted to be a 404-amino acid protein with several transmembrane domains localizing in the plasma membrane. The RT-PCR demonstrated a high expression of ichthyin in brain, lung, stomach, skin, and leukocytes. Lefevre et al. (2004) proposed that ichthyin protein was a membrane receptor for a ligand, probably trioxilin A3, from the hepoxilin pathway.

Lefevre et al. (2004) identified a gene for a new form of non-syndromic autosomal recessive congenital ichthyosis (ARCI) and studied its genomic localization by homozygosity mapping. The study included two sisters with ARCI from a consanguineous Syrian family. They were born as collodion babies. Both sisters had palmoplanter keratoderma, often yellowish with fissures. Lefevre et al. (2004) identified a new gene in those patients (ichthyin). Sequencing of ichthyin gene showed the presence of a missense mutation in exon 5 (523C-to-G).