The genes ALOX12B and ALOXE3 belongs to the group of lipoxygenases, and encode enzymes that modify lipids involved in the differentiation of the epidermis. Loss of function of these proteins leads to congenital ichthyosiform erythroderma or lamellar ichthyosis, a rare skin disease affecting about one out of 135 000 to 300 000 individuals.
We examine the whole coding sequence of both genes, including exon-intron connections (15 exons of the ALOX12B gene, 17 exons of the ALOXE3 gene). For the purpose of this examination, we use PCR amplification of given sections and direct sequencing.
Mutations in the ALOX12B and ALOXE3 genes occur in 17% of patients with phenotype of congenital ichthyosiform erythroderma or lamellar ichthyosis. About 60% of this is mutation of ALOX12B gene and 40% are mutations of ALOXE3 gene (1,2). Sequencing of the coding sequence and exon-intron connections covers 100% of known mutations of ALOX12B and ALOXE3.
Analytical sensitivity and specificity of sequencing: 99 %.
Mutations deep in the intronic and regulatory sequences are not captured. Deletions and duplications will not be captured. Rare polymorphisms in place of primers settlement may cause a diagnostic error. In the case of mosaicism, if the altered cell line is not represented at least by 20%, the mutations in ALOX12B and ALOXE3 are not captured.
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