RESUMEN
Objective To analyze mutations in the cathepsin C (CTSC) gene in a patient with Papillon-Lefèvre syndrome (PLS).Methods Clinical data were collected from a patient with PLS.Two milliliters of venous blood samples were obtained from the patient,his parents and 100 unrelated healthy controls separately.DNA was extracted from these blood samples,and PCR was performed to amplify all the 7 exons of the CTSC gene followed by direct DNA sequencing.Results Two heterozygous mutations were observed in the CTSC gene of the patient.One was a novel mutation c.824C ＞ T at position 824 in the exon 6,which resulted in a substitution of ACC (threonine) by ATC (isoleucine) at codon 275 (p.T275I).The other one was the mutation c.1040A ＞ G at position 1040 in the exon 7,causing the substitution of TAT (tyrosine) by TGT (cysteine) at codon 347 (p.Y347C).His father and mother carried the heterozygous mutation c.824C ＞ T and c.1040A ＞ G respectively.Neither of the two mutations was observed in the 100 healthy controls.Conclusions CTSC mutations are responsible for the clinical phenotype of PLS.Identification of the c.824C ＞ T mutation extends the spectrum of mutations in the CTSC gene and provides a basis for genetic diagnosis of PLS.