Impaired neuronal KCC2 function by biallelic SLC12A5 mutations in migrating focal seizures and severe developmental delay.
Impaired neuronal KCC2 function by biallelic SLC12A5 mutations in migrating focal seizures and severe developmental delay.
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DOI：
10.1038/srep30072
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发表时间：
2016-07-20
影响因子：
4.6
通讯作者：
Matsumoto N
中科院分区：
文献类型：
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作者：
Saitsu H;Watanabe M;Akita T;Ohba C;Sugai K;Ong WP;Shiraishi H;Yuasa S;Matsumoto H;Beng KT;Saitoh S;Miyatake S;Nakashima M;Miyake N;Kato M;Fukuda A;Matsumoto N
婴儿癫痫伴移行性局灶性发作（Epilepsy of infant with migrating focal seizures，EIMFS）是一种以移行性多形性局灶性发作为特征的早发性癫痫综合征。10例散发性和1例家族性EIMFS的全外显子组测序（WES）显示SLC 12 A5复合杂合子（编码神经元K+-Cl−共转运蛋白KCC 2）突变在两个家庭：c.279 + 1G > C导致转录物中外显子3的跳跃E50_Q93del）和c.572 C >T（p.A191V），以及在个体3中c.967T > C（p.S323P）和c.1243 A > G（p.M415V）。通过检索来自526名患者的WES数据和来自141名婴儿癫痫患者的SLC 12 A5靶向重测序数据，鉴定了另一名患有迁移性多灶性癫痫发作和复合杂合突变[c.953G > C（p.W318S）和c.2242_2244del（p.S748del）]的患者（个体4）。短杆菌肽穿孔膜片钳分析表明，E50_Q93del和M415 V突变体的Cl−挤出功能受到强烈抑制，A191 V和S323 P突变体的功能轻度受损。这些KCC 2突变体的细胞表面表达水平与野生型KCC 2相似。两个KCC 2突变体的异源表达，模拟患者状态，产生了比野生型KCC 2显著更高的细胞内Cl−水平，但低于没有KCC 2。这些数据清楚地表明，由个体中两种类型的差异受损的KCC 2突变体介导的部分破坏的神经元Cl−外排导致EIMFS。
Epilepsy of infancy with migrating focal seizures (EIMFS) is one of the early-onset epileptic syndromes characterized by migrating polymorphous focal seizures. Whole exome sequencing (WES) in ten sporadic and one familial case of EIMFS revealed compound heterozygous SLC12A5 (encoding the neuronal K+-Cl− co-transporter KCC2) mutations in two families: c.279 + 1G > C causing skipping of exon 3 in the transcript (p.E50_Q93del) and c.572 C >T (p.A191V) in individuals 1 and 2, and c.967T > C (p.S323P) and c.1243 A > G (p.M415V) in individual 3. Another patient (individual 4) with migrating multifocal seizures and compound heterozygous mutations [c.953G > C (p.W318S) and c.2242_2244del (p.S748del)] was identified by searching WES data from 526 patients and SLC12A5-targeted resequencing data from 141 patients with infantile epilepsy. Gramicidin-perforated patch-clamp analysis demonstrated strongly suppressed Cl− extrusion function of E50_Q93del and M415V mutants, with mildly impaired function of A191V and S323P mutants. Cell surface expression levels of these KCC2 mutants were similar to wildtype KCC2. Heterologous expression of two KCC2 mutants, mimicking the patient status, produced a significantly greater intracellular Cl− level than with wildtype KCC2, but less than without KCC2. These data clearly demonstrated that partially disrupted neuronal Cl− extrusion, mediated by two types of differentially impaired KCC2 mutant in an individual, causes EIMFS.