Exome sequencing and systems biology converge to identify novel mutations in the L-type calcium channel, CACNA1C, linked to autosomal dominant long QT syndrome.
Exome sequencing and systems biology converge to identify novel mutations in the L-type calcium channel, CACNA1C, linked to autosomal dominant long QT syndrome.
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DOI：
10.1161/circgenetics.113.000138
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发表时间：
2013-06
期刊：
影响因子：
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通讯作者：
Ackerman MJ
中科院分区：
文献类型：
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作者：
Boczek NJ;Best JM;Tester DJ;Giudicessi JR;Middha S;Evans JM;Kamp TJ;Ackerman MJ
长QT综合征（LQTS）是最常见的心脏通道病变，有15个已知的LQTS易感基因。大约20%的LQTS病例在基因上仍然难以捉摸。我们结合了全外显子组测序（WES）和生物信息学/系统生物学，在一个多代谱系中确定了导致非综合征性、基因型阴性、常染色体显性LQTS的致病底物，并在102名基因型阴性/表型阳性LQTS的无亲缘关系患者中确定了所阐明基因的谱和变异流行率。WES用于基因型阴性/表型阳性家族的三名成员。基因组三角测量结合生物信息学工具和排序算法鉴定了CACNA1C突变。该突变名为Pro857Arg-CACNA1C，在家系中与该疾病共分离，通过三种疾病网络算法将其列为最可能的lqts易感基因，并且涉及II-III连接体中位于PEST区域的保守残基。功能研究表明，与野生型相比，Pro857Arg-CACNA1C导致ICa、L增加和通道表面膜表达增加的功能获得。随后的突变分析在我们的102例不相关的基因型阴性/表型阳性LQTS患者中发现了3个额外的CACNA1C变异。其中两个变体还涉及Cav1.2的PEST结构域内的保守残基。这项研究提供了证据，证明WES和生物信息学/系统生物学的结合是识别潜在致病基因/突变的有效策略。在单个家系中，功能性CACNA1C突变与疾病共分离的鉴定表明，在没有Timothy综合征的情况下，CACNA1C扰动可能是常染色体显性LQTS的基础。
Long QT syndrome (LQTS) is the most common cardiac channelopathy with 15 elucidated LQTS-susceptibility genes. Approximately 20% of LQTS cases remain genetically elusive. We combined whole exome sequencing (WES) and bioinformatic/systems biology to identify the pathogenic substrate responsible for non-syndromic, genotype-negative, autosomal dominant LQTS in a multigenerational pedigree and established the spectrum and prevalence of variants in the elucidated gene among a cohort of 102 unrelated patients with “genotype-negative/phenotype-positive” LQTS. WES was utilized on three members within a genotype-negative/phenotype-positive family. Genomic triangulation combined with bioinformatic tools and ranking algorithms led to the identification of a CACNA1C mutation. This mutation, Pro857Arg-CACNA1C, co-segregated with the disease within the pedigree, was ranked by three disease-network algorithms as the most probable LQTS-susceptibility gene, and involves a conserved residue localizing to the PEST domain in the II–III linker. Functional studies reveal that Pro857Arg-CACNA1C leads to a gain-of-function with increased ICa,L and increased surface membrane expression of the channel compared to wildtype. Subsequent mutational analysis identified 3 additional variants within CACNA1C in our cohort of 102 unrelated cases of genotype-negative/phenotype-positive LQTS. Two of these variants also involve conserved residues within Cav1.2’s PEST domain. This study provides evidence that coupling WES and bioinformatic/systems biology is an effective strategy for the identification of potential disease causing genes/mutations. The identification of a functional CACNA1C mutation co-segregating with disease in a single pedigree suggests that CACNA1C perturbations may underlie autosomal dominant LQTS in the absence of Timothy syndrome.