Abstract: Objective To identify gene mutations of two cases of epidermolytic hyperkeratosis ichthyosis.Methods Punch biopsies were taken from typical lesions for histopathological examination by light microscopy and transmission electron microscopy.Genomic DNA was extracted from blood samples.Mutations of keratin1(K1)and keratin10(K10)were detected by polymerase chain reaction(PCR)and DNA sequencing;Frequencies of the alleles were screened by PCR-based allele-specific assays(PASA)and restriction fragment-length polymorphism(RFLP)in normal controls.Results There was a single heterozygous point mutation in either K1 or K10 genes,i.e.2140G→A of K10 gene and 4226G→A of K1gene,leading to an amino acid alteration of arginine to histidine(K10R156H)and glutamic acid to lysine(K1E477K),respectively.These substitutions were not found in normal controls.Conclusion K10R156H and K1E477K mutations were the cause of the phenotypes in these two cases.

Key words: Ichthyosis, Keratin, Genes, Mutation