OBJECTIVEThis study aims to investigate the gene mutational characteristics of cathepsin C (CTSC) gene in a Chinese patient with Papillon-Lefèvre syndrome (PLS), then further confirm the genetic basis for the phenotype of PLS, and obtain genetic information that can be used as guide in the diagnosis and treatment of PLS.

METHODSWith their consent, peripheral blood samples were obtained from the proband and his family members (his parents and older sister) for genomic DNA extraction. The coding region and exon/intron boundaries of the CTSC gene were amplified and sequenced using poly-merase chain reaction and direct sequencing of DNA.

RESULTSCompound heterozygous mutations of CTSC gene were iden-tified in the patient. The proband carries one heterozygous nonsense mutation c.754C>T in exon 5 and one heterozygous missense mutation c.1040A>G in exon 7. Both parents were heterozygous carriers without the clinical symptoms of PLS. None of the mutations were detected in the proband's sister.

CONCLUSIONSThe study proves that mutations of CTSC gene are responsible for the phenotype of Papillon-Lefèvre syndrome.
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