A KRT6A and a Novel KRT16 Gene Mutations in Chinese Patients with Pachyonychia Congenita

BACKGROUND: Pachyonychia congenita (PC) is a rare, autosomal dominant genodermatosis characterized by palmoplantar keratoderma, nail dystrophy, cystic lesions, follicular hyperkeratosis, mucosal leukokeratoses, hyperhidrosis, hoarseness, and, rarely, natal teeth. Five keratin genes, KRT6A, KRT6B, KRT6C, KRT16 and KRT17, have been found to be associated with PC. METHODS: Using polymerase chain reaction and Sanger sequencing techniques, the purpose of the present study was to investigate the clinical features associated with PC and discover disease-associated variants. The KRT6A, KRT16, KRT17, and KRT6B exonic and flanking region sequences were amplified and directly sequenced to detect mutations. RESULTS: Across two independent instances of PC, we identified a previously reported c.1393T>C (p.Tyr465His) mutation in exon 7 of KRT6A, and a novel c.1237G>C (p.Glu413Gln) heterozygous missense mutation in exon 6 of the KRT16 gene. CONCLUSION: Through phenotype-genotype analysis among PC pedigrees, confirmed diagnoses of PC-K6a and PC-K16 were made in the two patients who presented with symptoms of PC. A new pathogenic mutation site in PC-K16 was potentially discovered.