Ion channels are crucial in the generation and modulation of excitability in the nervous system and have been implicated in human epilepsy. Forty-one epilepsyassociated ion channel genes and their mutations are system...Ion channels are crucial in the generation and modulation of excitability in the nervous system and have been implicated in human epilepsy. Forty-one epilepsyassociated ion channel genes and their mutations are systematically reviewed. In this paper, we analyzed the genotypes, functional alterations（funotypes）, and phenotypes of these mutations. Eleven genes featured loss-offunction mutations and six had gain-of-function mutations.Nine genes displayed diversified funotypes, among which a distinct funotype-phenotype correlation was found in SCN1A. These data suggest that the funotype is an essential consideration in evaluating the pathogenicity of mutations and a distinct funotype or funotype-phenotype correlation helps to define the pathogenic potential of a gene.展开更多
This study examined the current changes of human ether-a-go-go-related gene （hERG） mutation derived from a LQT2 Chinese family with a highly penetrating phenotype. Mutation was identi-fied and site-directed mutagene...This study examined the current changes of human ether-a-go-go-related gene （hERG） mutation derived from a LQT2 Chinese family with a highly penetrating phenotype. Mutation was identi-fied and site-directed mutagenesis was performed to induce the mutation in wild-type （WT） hERG. WT hERG and mutated V535M were cloned and transiently expressed in HEK293 cells. At the 48th and 72nd h after transfection, membrane currents were recorded using whole cell patch-clamp procedures. An A〉G transition at 1605 resulting in replacement of V535M was identified. Compared to WT, V535M mutation significantly decreased tail currents of hERG. At test potential of-40 mV after depolarizing at ＋50 mV, tail current densities were 83.354-7.06 pA/pF in WT and 50.38-4-7.74 pA/pF in V535M respectively （n=20, P〈0.01）. Gating kinetics of bERG revealed that Vl/2 of steady-state inactivation shifted to negative potential in the mutant （V1/2,v535M： -61.814-1.7 mV vs. V1/2, wx： -43.1q-0.71 mV）. The time constant of recovery from inactivation was markedly prolonged in the mutant compared to WT among test potentials. V535M hERG mutation demonstrated markedly decreased tail current densities, which suggests that V535M is a new loss-of-function mutation of hERG channel responsible for LQT2.展开更多
基金supported by the National Natural Science Foundation of China (81571273,81571274,81501124,81271434,and 81301107)Omics-based precision medicine of epilepsy being entrusted by Key Research Project of the Ministry of Science and Technology of China (2016YFC0904400)+5 种基金the Natural Science Foundation of Guangdong Province,China (2014A030313489)Science and Technology Planning Projects of Guangdong Province,China (2012B031800404 and 2013B051000084)the Department of Education of Guangdong Province,China (2013CXZDA022,2013KJCX0156,and 2012KJCX009)the Foundation for High-level Talents in Higher Education of Guangdong Province,China (2013-167)Yangcheng Scholar Research Projects of Guangzhou Municipal College (12A016S and 12A017G)Science and Technology Projects of Guangzhou,Guangdong Province,China (2014J4100069,201508020011,201604020161,and 201607010002)
文摘Ion channels are crucial in the generation and modulation of excitability in the nervous system and have been implicated in human epilepsy. Forty-one epilepsyassociated ion channel genes and their mutations are systematically reviewed. In this paper, we analyzed the genotypes, functional alterations（funotypes）, and phenotypes of these mutations. Eleven genes featured loss-offunction mutations and six had gain-of-function mutations.Nine genes displayed diversified funotypes, among which a distinct funotype-phenotype correlation was found in SCN1A. These data suggest that the funotype is an essential consideration in evaluating the pathogenicity of mutations and a distinct funotype or funotype-phenotype correlation helps to define the pathogenic potential of a gene.
文摘This study examined the current changes of human ether-a-go-go-related gene （hERG） mutation derived from a LQT2 Chinese family with a highly penetrating phenotype. Mutation was identi-fied and site-directed mutagenesis was performed to induce the mutation in wild-type （WT） hERG. WT hERG and mutated V535M were cloned and transiently expressed in HEK293 cells. At the 48th and 72nd h after transfection, membrane currents were recorded using whole cell patch-clamp procedures. An A〉G transition at 1605 resulting in replacement of V535M was identified. Compared to WT, V535M mutation significantly decreased tail currents of hERG. At test potential of-40 mV after depolarizing at ＋50 mV, tail current densities were 83.354-7.06 pA/pF in WT and 50.38-4-7.74 pA/pF in V535M respectively （n=20, P〈0.01）. Gating kinetics of bERG revealed that Vl/2 of steady-state inactivation shifted to negative potential in the mutant （V1/2,v535M： -61.814-1.7 mV vs. V1/2, wx： -43.1q-0.71 mV）. The time constant of recovery from inactivation was markedly prolonged in the mutant compared to WT among test potentials. V535M hERG mutation demonstrated markedly decreased tail current densities, which suggests that V535M is a new loss-of-function mutation of hERG channel responsible for LQT2.
