Abstract： Objective To identify keratin gene mutation in a Chinese family with pachyonychia congenita (PC).Methods Blood samples were collected from 2 patients and 4 unaffected family members in a Chinese family with PC.Genomic DNA extracted from the proband was subjected to the amplification of all exons and their intronic and flanking sequences of the KRT17 gene as well as the helix initiation and termination motifs of the KRT6B gene by PCR,followed by gene sequencing with the Sanger method.Then,the mutations of KRT17 and KRT6B genes detected in the proband were screened in the other family members.Results A missense mutation c.263 T ＞ C (p.M88T) in KRT17 gene,which results in a substitution of mcthionine (M) by threonine (T) at position 88 of the keratin 17,was observed in the 2 patients in this family.No mutation was found in the KRT6B gene in any of the family members or in the KRT17 gene in unaffected family members.Conclusion The missense mutation c.263T ＞ C (p.M88T) in KRT17 gene is likely to be a causative mutation of PC in this family.