OBJECTIVETo investigate the mutational characteristics of the cathepsin C gene (CTSC, also known as dipeptidyl-peptidase I gene, DPP I) in a family of Han nationality with Papillon-Lefevre syndrome, and to provide the molecular basis for the phenotype.

METHODSGenomic DNAs were extracted from the proband, his parents and younger sister after informed consent. Polymerase chain reaction and direct DNA sequencing were carried out to screen the mutations of the cathepsin C gene.

RESULTSCompound heterozygous mutations of the cathepsin C gene were identified in the patient. The patient carried one frameshift mutation 116delG in exon 1, one heterozygous mutation C255S in exon 6, one missense mutation F314S and one sense mutation E335E in exon 7. The four changes were novel mutations of the cathepsin C gene, which had not been reported previously. None of the mutations were detected in normal controls.

CONCLUSIONMutations of the cathepsin C gene are probably responsible for the phenotype of Papillon-Lefevre syndrome in this family.