Objective: To analyze potential mutation of keration 9 gene (KRT9) in a Chinese family affected with epidermolytic palmoplantar keratoderma (EPPK) and to correlate genotype with the phenotype.
Methods: Genomic DNA was extracted from peripheral blood samples of 12 patients and 13 healthy individuals from the family and 100 unrelated individuals. Polymerase chain reaction (PCR) was used to amplify exons 1 and 6 of KRT9 gene. PCR products were sequenced bidirectionally in order to identify potential mutations.
Results: A heterozygous transversional mutation, 488G→A, was identified in exon 1 of KRT9 gene in all patients, which has resulted in substitution of a glutamine residue for arginine acid at position 163 (R163Q) of the KRT9 protein. The same mutation was not found in the 13 healthy members from the family and 100 unrelated individuals.
Conclusion: The 488G→A mutation of KRT9 gene is probably the cause of EPPK in this Chinese family.