Objective: To map and identify the disease gene for the epidermolytic palmoplantar keratoderma (EPPK) in a Uighur family of China.
Methods: Blood samples were collected and genomic DNA was extracted from 48 members of the Xinjiang Uighur family. Six microsatellite repeat sequences on chromosome region 17q12-q21 and 12q13 were selected based on the two known candidate genes KRT9 and KRT1. Two-point linkage analysis and haplotype analysis were performed. Exons and their flanking intronic sequence of the KRT9 gene were amplified by polymerase chain reaction (PCR) and sequenced.
Results: Data from the marker D17S1787 suggested linkage and yielded a Lod score of 8.65 at theta=0 by using MLINK software. Genotypes and haplotypes were acquired. The disease gene of the EPPK family is located between markers 17/TG/36620115 and D17S846. Chromosome 12q13 region was excluded with the negative Lod score obtained in marker D12S96 (Lod=-infinity at theta=0). No pathogenic mutation was detected in the KRT9 gene.
Conclusion: The disease gene of the EPPK family is located on chromosome region 17q21.2. The keratin 9 gene might not be the disease gene.