[Gene mutational analyses of cathepsin C gene in a family with Papillon-Lefèvre syndrome].

This study aimed to investigate the gene mutational characteristics of cathepsin C (CTSC) gene in a Chinese patient with Papillon-Lefèvre syndrome (PLS) and further confirm the genetic basis for the phenotype of PLS.Peripheral blood samples were obtained from the PLS proband and his family members (his parents and younger brother) for genomic DNA extraction. The coding region and exon boundaries of the CTSC gene were amplified and sequenced by polymerase chain reaction and direct sequencing of DNA.Compound heterozygous mutations of CTSC gene were identified in the patient. A heterozygous missense mutation occurred in the 800th base of exon 6, and the base T in the base pair was replaced by C (c.800T>C). The encoded amino acid leucine changed to proline (p. L267P). A heterozygous missense mutation occurred in the 1015th base of exon 7, and base C in the base pair was replaced by T (c.1015C>T). The encoded amino acid arginine changed to cysteine (p.R339C). Among the mutations, c.800T>C originated from the mother, c.1015C>T was identified from the father. No mutations were detected in the younger brother.Mutations of CTSC gene are responsible for the phenotype of PLS.目的 对一个掌跖角化-牙周破坏综合征（PLS）患者及其家系组织蛋白酶C基因（CTSC）突变位点进行分析，探讨PLS的分子致病机制。方法 提取1例PLS先证者及其直系血亲（父母、弟弟）的基因组DNA，应用聚合酶链反应和DNA直接测序技术分析先证者及其直系血亲CTSC基因的突变情况。结果 PLS先证者CTSC基因存在复合型杂合突变。先证者位于外显子6的第800位碱基发生了一个杂合错义突变，该碱基对中的碱基T被C取代（c.800T> C），其编码的氨基酸由亮氨酸改变为脯氨酸（p.L267P）；位于外显子7的第1015位碱基发生了一个杂合错义突变，该碱基对中的碱基C被T取代（c.1015C>T），其编码的氨基酸由精氨酸改变为半胱氨酸（p.R339C）。其中，c.800T> C来自母亲，c.1015C>T来自父亲，弟弟的CTSC基因未见突变。结论 PLS的临床表征与CTSC基因突变有关。.