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Abstract：
BACKGROUND: Progressive cardiac conduction defect (PCCD), also known as Lenegre-Lev disease, is one of the most common heart conduction abnormalities. Previous studies have screened for known mutation sites that cause heart block in a 68-person family with a history of PCCD, revealed no mutations.
OBJECTIVE: To screen pathogenic genes of the PCCD family and to study the function of the gene mutations related to heart block diseases.
METHODS: Whole exome sequencing (WES) was performed on two PCCD patients and one non-PCCD family member to find the related pathogenic gene. After family co-segregation and preliminary functional analysis, we identified the mutant gene CLCA2. To study the function of this gene, we constructed mutant-gene mice using CRISPR-Cas9 technology, and electrocardiogram monitoring was performed after genotype verification.
RESULTS: The CLCA2 c.G1725T mutation was identified and co-segregated with the phenotype. The analysis showed that the CLCA2 c.G1725T mutation is harmful and mainly affects protein glycosylation. Immunofluorescence staining revealed that CLCA2 was highly expressed in the sinoatrial node (SAN) tissues. Electrocardiogram monitoring of the mice revealed that CLCA2 point mutations induced mild conduction block and ectopic pacemakers.
CONCLUSIONS: Our findings indicate that a novel heterozygous missense mutation c.G1725T of the CLCA2 gene may be associated with heart block disease and the mutation in this gene may lead to sinus node lesions and conduction blocking.
OBJECTIVE: To screen pathogenic genes of the PCCD family and to study the function of the gene mutations related to heart block diseases.
METHODS: Whole exome sequencing (WES) was performed on two PCCD patients and one non-PCCD family member to find the related pathogenic gene. After family co-segregation and preliminary functional analysis, we identified the mutant gene CLCA2. To study the function of this gene, we constructed mutant-gene mice using CRISPR-Cas9 technology, and electrocardiogram monitoring was performed after genotype verification.
RESULTS: The CLCA2 c.G1725T mutation was identified and co-segregated with the phenotype. The analysis showed that the CLCA2 c.G1725T mutation is harmful and mainly affects protein glycosylation. Immunofluorescence staining revealed that CLCA2 was highly expressed in the sinoatrial node (SAN) tissues. Electrocardiogram monitoring of the mice revealed that CLCA2 point mutations induced mild conduction block and ectopic pacemakers.
CONCLUSIONS: Our findings indicate that a novel heterozygous missense mutation c.G1725T of the CLCA2 gene may be associated with heart block disease and the mutation in this gene may lead to sinus node lesions and conduction blocking.
摘要：
背景：进行性心脏传导缺损（PCCD），也被称为Lenegre-Lev病，是最常见的心脏传导异常之一。先前的研究已经在一个有PCCD病史的68人家庭中筛选了导致心脏传导阻滞的已知突变位点，没有发现突变.
目的：筛选PCCD家族致病基因并研究其与心脏传导阻滞疾病相关基因突变的功能。
方法：对两名PCCD患者和一名非PCCD家族成员进行全外显子组测序（WES），以寻找相关致病基因。经过家庭共同隔离和初步功能分析，我们鉴定了突变基因CLCA2。为了研究这个基因的功能，我们使用CRISPR-Cas9技术构建了突变基因小鼠，基因型验证后进行心电图监测。
结果：鉴定了CLCA2c.G1725T突变，并与表型共分离。分析表明，CLCA2c.G1725T突变是有害的，主要影响蛋白质的糖基化。免疫荧光染色显示CLCA2在窦房结（SAN）组织中高表达。对小鼠的心电图监测显示，CLCA2点突变可引起轻度传导阻滞和异位起搏器。
结论：我们的研究结果表明，CLCA2基因的一个新的杂合错义突变c.G1725T可能与心脏传导阻滞疾病相关，该基因的突变可能导致窦房结病变和传导阻滞。
目的：筛选PCCD家族致病基因并研究其与心脏传导阻滞疾病相关基因突变的功能。
方法：对两名PCCD患者和一名非PCCD家族成员进行全外显子组测序（WES），以寻找相关致病基因。经过家庭共同隔离和初步功能分析，我们鉴定了突变基因CLCA2。为了研究这个基因的功能，我们使用CRISPR-Cas9技术构建了突变基因小鼠，基因型验证后进行心电图监测。
结果：鉴定了CLCA2c.G1725T突变，并与表型共分离。分析表明，CLCA2c.G1725T突变是有害的，主要影响蛋白质的糖基化。免疫荧光染色显示CLCA2在窦房结（SAN）组织中高表达。对小鼠的心电图监测显示，CLCA2点突变可引起轻度传导阻滞和异位起搏器。
结论：我们的研究结果表明，CLCA2基因的一个新的杂合错义突变c.G1725T可能与心脏传导阻滞疾病相关，该基因的突变可能导致窦房结病变和传导阻滞。
