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Karan KR, Satishchandra P, Sinha S, Anand A. A genetic locus for sensory epilepsy precipitated by contact with hot water maps to chromosome 9p24.3-p23. J Genet 2018. [DOI: 10.1007/s12041-018-0947-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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2
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Chen T, Giri M, Xia Z, Subedi YN, Li Y. Genetic and epigenetic mechanisms of epilepsy: a review. Neuropsychiatr Dis Treat 2017; 13:1841-1859. [PMID: 28761347 PMCID: PMC5516882 DOI: 10.2147/ndt.s142032] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Epilepsy is a common episodic neurological disorder or condition characterized by recurrent epileptic seizures, and genetics seems to play a key role in its etiology. Early linkage studies have localized multiple loci that may harbor susceptibility genes to epilepsy, and mutational analyses have detected a number of mutations involved in both ion channel and nonion channel genes in patients with idiopathic epilepsy. Genome-wide studies of epilepsy have found copy number variants at 2q24.2-q24.3, 7q11.22, 15q11.2-q13.3, and 16p13.11-p13.2, some of which disrupt multiple genes, such as NRXN1, AUTS2, NLGN1, CNTNAP2, GRIN2A, PRRT2, NIPA2, and BMP5, implicated for neurodevelopmental disorders, including intellectual disability and autism. Unfortunately, only a few common genetic variants have been associated with epilepsy. Recent exome-sequencing studies have found some genetic mutations, most of which are located in nonion channel genes such as the LGI1, PRRT2, EFHC1, PRICKLE, RBFOX1, and DEPDC5 and in probands with rare forms of familial epilepsy, and some of these genes are involved with the neurodevelopment. Since epigenetics plays a role in neuronal function from embryogenesis and early brain development to tissue-specific gene expression, epigenetic regulation may contribute to the genetic mechanism of neurodevelopment through which a gene and the environment interacting with each other affect the development of epilepsy. This review focused on the analytic tools used to identify epilepsy and then provided a summary of recent linkage and association findings, indicating the existence of novel genes on several chromosomes for further understanding of the biology of epilepsy.
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Affiliation(s)
- Tian Chen
- Department of Health Management Center, Chongqing Three Gorges Central Hospital, Chongqing, People's Republic of China
| | - Mohan Giri
- National Center for Rheumatic Diseases, Ratopul, Gaushala, Kathmandu, Nepal
| | - Zhenyi Xia
- Department of Thoracic Surgery, Chongqing Three Gorges Central Hospital, Chongqing, People's Republic of China
| | - Yadu Nanda Subedi
- National Center for Rheumatic Diseases, Ratopul, Gaushala, Kathmandu, Nepal
| | - Yan Li
- Department of Health Management Center, Chongqing Three Gorges Central Hospital, Chongqing, People's Republic of China
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Layouni S, Salzmann A, Guipponi M, Mouthon D, Chouchane L, Dogui M, Malafosse A. Genetic linkage study of an autosomal recessive form of juvenile myoclonic epilepsy in a consanguineous Tunisian family. Epilepsy Res 2010; 90:33-8. [PMID: 20378313 DOI: 10.1016/j.eplepsyres.2010.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Revised: 03/01/2010] [Accepted: 03/07/2010] [Indexed: 11/15/2022]
Abstract
Juvenile myoclonic epilepsy (JME) is the most common idiopathic generalized epilepsies (IGEs), affecting 12-30% of all epilepsies in medical centers. To date genetic linkage studies have revealed putative loci on different chromosomes, but these findings are still inconclusive about which gene precisely is responsible for the disease. Here, we report the genetic and clinical analysis of a (JME) consanguineous Tunisian family with four affected children out of eight. A genome-wide search was carried out by using the Affymetrix GeneChip Mapping 500K NspI chip. Pairewise logarithm of the odds (LOD) scores were calculated with MERLIN (1.1) assuming an autosomal recessive model, and a complementary homozygous mapping analysis was performed with AutoSNPa software. The genome-wide parametric linkage analysis showed suggestive linkage to chromosome 2q. Interactive visual analysis of SNP data using AutoSNPa revealed two large regions of shared homozygosity by descent on 2q23.3 and on 2q24.1. We decided to sequence the exons of the two genes coding for such proteins located in 2q23.3, CACNB4 and 2q24.1, KCNJ3. No nucleotide variation--comprising the previously reported mutations--was detected.
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Affiliation(s)
- Samia Layouni
- Department of Physiology, Faculty of Medicine, Monastir, Tunisia.
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4
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Layouni S, Chouchane L, Malafosse A, Dogui M. Dimorphism of TAP-1 gene in Caucasian with juvenile myoclonic epilepsy and in Tunisian with idiopathic generalized epilepsies. Int J Immunogenet 2010; 37:117-23. [PMID: 20141545 DOI: 10.1111/j.1744-313x.2010.00900.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Juvenile myoclonic epilepsy (JME) is the most common form of idiopathic generalized epilepsies (IGE) that account for about 5-10% of all types of epilepsies. The first putative locus termed EJM1 is on the human leucocyte antigen (HLA-II) region of chromosome 6p21.3. Interestingly, the EJM1 region includes the Transporter associated with antigen processing 1 (TAP-1) gene encoding the TAP-1, and previous studies have reported associations between HLA-II polymorphisms and different types of epilepsy. In this study, we report an association between two TAP-1 functional polymorphisms the I333V and the D637G and most common IGE in Tunisian population, but we fail to find significant results in Caucasian with JME.
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Affiliation(s)
- S Layouni
- Department of Physiology, Faculty of Medicine, Monastir, Tunisia.
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Alkelai A, Kohn Y, Olender T, Sarner-Kanyas K, Rigbi A, Hamdan A, Ben-Asher E, Lancet D, Lerer B. Evidence for an interaction of schizophrenia susceptibility loci on chromosome 6q23.3 and 10q24.33-q26.13 in Arab Israeli families. Am J Med Genet B Neuropsychiatr Genet 2009; 150B:914-25. [PMID: 19152384 DOI: 10.1002/ajmg.b.30918] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A genome scan for schizophrenia related loci in Arab Israeli families by Lerer et al. [Lerer et al. (2003); Mol Psychiatry 8:488-498] detected significant evidence for linkage at chromosome 6q23. Subsequent fine mapping [Levi et al. (2005); Eur J Hum Genet 13:763-771], association [Amann-Zalcenstein et al. (2006); Eur J Hum Genet 14:1111-1119] and replication studies [Ingason et al. (2007); Eur J Hum Genet 15:988-991] identified AHI1 as a putative susceptibility gene. The same genome scan revealed suggestive evidence for a schizophrenia susceptibility locus in the 10q23-26 region. Genes at these two loci may act independently in the pathogenesis of the disease in our homogeneous sample of Arab Israeli families or may interact with each other and with other factors in a common biological pathway. The purpose of our current study was to test the hypothesis of genetic interaction between these two loci and to identify the type of interaction between them. The initial stage of our study focused on the 10q23-q26 region which has not been explored further in our sample. The second stage of the study included a test for possible genetic interaction between the 6q23.3 locus and the refined 10q24.33-q26.13 locus. A final candidate region of 19.9 Mb between markers D10S222 (105.3 Mb) and D10S587 (125.2 Mb) was found on chromosome 10 by non-parametric and parametric linkage analyses. These linkage findings are consistent with previous reports in the same chromosomal region. Two-locus multipoint linkage analysis under three complex disease inheritance models (heterogeneity, multiplicative, and additive models) yielded a best maximum LOD score of 7.45 under the multiplicative model suggesting overlapping function of the 6q23.3 and 10q24.33-q26.13 loci.
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Affiliation(s)
- A Alkelai
- Biological Psychiatry Laboratory, Department of Psychiatry, Hadassah-Hebrew University Medical Center, Ein Karem, Jerusalem, Israel
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6
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Ratnapriya R, Satishchandra P, Kumar SD, Gadre G, Reddy R, Anand A. A locus for autosomal dominant reflex epilepsy precipitated by hot water maps at chromosome 10q21.3-q22.3. Hum Genet 2009; 125:541-9. [PMID: 19266219 DOI: 10.1007/s00439-009-0648-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 02/25/2009] [Indexed: 11/26/2022]
Abstract
Hot water epilepsy (HWE) is a form of reflex or sensory epilepsy wherein seizures are precipitated by an unusual stimulus, the contact of hot water over the head and body. Genome-wide linkage analysis of a large family with ten affected members, provided evidence of linkage (Z (max) = 3.17 at theta = 0 for D10S412) to chromosome 10q21. Analysis of five additional HWE families, for markers on chromosome 10, further strengthened the evidence of linkage to the same chromosomal region with three out of five families showing concordance for the disease haplotype and providing a two-point LOD score of 4.86 at theta = 0 and 60% penetrance for D10S412. The centromere-proximal and -distal boundaries of the critical genetic interval of about 15 Mb at 10q21.3-q22.3 were defined by D10S581 and D10S201, respectively. Sequence analysis of a group of functional candidate genes, the ion channels KCNMA1, VDAC2 and solute carriers SLC25A16, SLC29A3 revealed no potentially pathogenic mutation. We propose to carry out further analysis of positional candidate genes from this region to identify the gene responsible for this unusual neurobehavioral phenotype.
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Affiliation(s)
- Rinki Ratnapriya
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
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Grill MF, Losey TE, Ng YT. The Hitchhiker's guide to the child neurologist's genetic evaluation of epilepsy. Semin Pediatr Neurol 2008; 15:32-40. [PMID: 18342259 DOI: 10.1016/j.spen.2008.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Over the past several decades, familial aggregation studies as well as twin studies have supported a genetic component to seizures. The recent advent of the genome project has served as a catalyst in the search for elucidating the hereditary influences of various epilepsies. Overlapping seizure features may lead to ambiguity when attempting to isolate a single phenotype. Conversely, the phenomenon of genetic heterogeneity implies that multiple genetic mutations may give rise to a similar phenotype. Despite valiant attempts at strictly defining epilepsy phenotype and mode of penetrance, one must also consider the role of environment in gene expression. Genetics (testing) in epilepsy is no longer limited to the idiopathic epilepsies but may have an equally significant role in the symptomatic epilepsies. This article guides the reader through the genetics of epilepsy via discussion of the phenotypic description of known genetic childhood epilepsy syndromes, illustration of the associated gene mutations identified thus far, and the implications of genetic testing in clinical practice.
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Affiliation(s)
- Marie F Grill
- Department of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013, USA
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Abstract
Very few genetic associations for idiopathic epilepsy have been replicated and this has tempered enthusiasm for the results of genetic studies in epilepsy. What are the reasons for lack of replication? While type 1 error, population stratification, and multiple testing have been discussed extensively, the importance of genetic heterogeneity has been relatively neglected. In the first part of this review, we explore the sources of genetic heterogeneity and their importance for epilepsy genetic studies. In the second part, we review alternatives to the simple law of replication, revisiting Bradford Hill's guidelines for evidence of causality. A coherence perspective is applied to three examples. We conclude that adopting the perspective of integrating coherent and consistent evidence from different experimental approaches is a more appropriate requirement for proceeding to functional studies.
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Affiliation(s)
- Deb K Pal
- Epidemiology Division, Department of Psychiatry, Columbia University Medical Center, New York, New York 10032, USA.
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Abstract
Genetic influences as causal factors in the epilepsies continue to be vigorously investigated, and we review several important studies of genes reported in 2006. To date, mutations in ion channel and neuroreceptor component genes have been reported in the small fraction of cases with clear Mendelian inheritance. These findings confirm that the so-called "channelopathies" are generally inherited as monogenic disorders. At the same time, the literature in common epilepsies abounds with reports of associations and reports of nonreplication of those association studies, primarily with channel genes. These contradictory reports can mostly be explained by confounding factors unique to genetic studies. The methodology of genetic studies and their common biases and confounding factors are also explained in this review. Amid the controversy, steady progress is being made on the epilepsies of complex inheritance, which represent the most common idiopathic epilepsy. Recent discoveries show that genes influencing the developmental assembly of neural circuits and neuronal metabolism may play a more prominent role in the common epilepsies than genes affecting membrane excitability and synaptic transmission.
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Affiliation(s)
- David A Greenberg
- Division of Statistical Genetics, Mailman School of Public Health, Columbia University Medical Center, 122 West 168th Street, 6th Floor, New York, NY 10032, USA.
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Abstract
One by one, mutation-containing mendelian genes that cause monogenic juvenile myoclonic epilepsies (JME) and single nucleotide polymorphisms (SNP)-susceptibility alleles that increase risks for nonmendelian complex JME should fall to the power of molecular genetics. Of 15 chromosome loci, 3 mendelian genes (alpha1-subunit of the GABA(A) receptor [GABRA1], chloride channel 2 gene [CLCN2], and Myoclonin1/EFHC1) and 2 SNP-susceptibility alleles of putative JME genes in epistases (bromodomain-containing protein 2 [BRD2] and connexin [Cx]-36) have been identified, so far. Antiepileptic drugs now can be designed against the specific molecular defects of JME.
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Affiliation(s)
- Antonio V Delgado-Escueta
- David Geffen School of Medicine, University of California Los Angeles Comprehensive Epilepsy Program, VA Greater Los Angeles Healthcare System West Los Angeles, CA, USA
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Stamm DS, Rampersaud E, Slifer SH, Mehltretter L, Siegel DG, Xie J, Hu-Lince D, Craig DW, Stephan DA, George TM, Gilbert JR, Speer MC. High-density single nucleotide polymorphism screen in a large multiplex neural tube defect family refines linkage to loci at 7p21.1-pter and 2q33.1-q35. ACTA ACUST UNITED AC 2006; 76:499-505. [PMID: 16933213 PMCID: PMC4169147 DOI: 10.1002/bdra.20272] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Neural tube defects (NTDs) are considered complex, with both genetic and environmental factors implicated. To date, no major causative genes have been identified in humans despite several investigations. The first genomewide screen in NTDs demonstrated evidence of linkage to chromosomes 7 and 10. This screen included 44 multiplex families and consisted of 402 microsatellite markers spaced approximately 10 cM apart. Further investigation of the genomic screen data identified a single large multiplex family, pedigree 8776, as primarily driving the linkage results on chromosome 7. METHODS To investigate this family more thoroughly, a high-density single nucleotide polymorphism (SNP) screen was performed. Two-point and multipoint linkage analyses were performed using both parametric and nonparametric methods. RESULTS For both the microsatellite and SNP markers, linkage analysis suggested the involvement of a locus or loci proximal to the telomeric regions of chromosomes 2q and 7p, with both regions generating a LOD* score of 3.0 using a nonparametric identity by descent relative sharing method. CONCLUSIONS The regions with the strongest evidence for linkage map proximal to the telomeres on these two chromosomes. In addition to mutations and/or variants in a major gene, these loci may harbor a microdeletion and/or translocation; potentially, polygenic factors may also be involved. This single family may be promising for narrowing the search for NTD susceptibility genes.
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Affiliation(s)
- Demetra S. Stamm
- Center for Human Genetics, Duke University Medical Center, Durham, NC
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC
| | | | - Susan H. Slifer
- Center for Human Genetics, Duke University Medical Center, Durham, NC
| | | | - Deborah G. Siegel
- Center for Human Genetics, Duke University Medical Center, Durham, NC
| | - Jianzhen Xie
- Center for Human Genetics, Duke University Medical Center, Durham, NC
| | | | | | | | - Timothy M. George
- Center for Human Genetics, Duke University Medical Center, Durham, NC
| | - John R. Gilbert
- Center for Human Genetics, Duke University Medical Center, Durham, NC
| | - Marcy C. Speer
- Center for Human Genetics, Duke University Medical Center, Durham, NC
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Hempelmann A, Taylor KP, Heils A, Lorenz S, Prud'homme JF, Nabbout R, Dulac O, Rudolf G, Zara F, Bianchi A, Robinson R, Gardiner RM, Covanis A, Lindhout D, Stephani U, Elger CE, Weber YG, Lerche H, Nürnberg P, Kron KL, Scheffer IE, Mulley JC, Berkovic SF, Sander T. Exploration of the Genetic Architecture of Idiopathic Generalized Epilepsies. Epilepsia 2006; 47:1682-90. [PMID: 17054691 DOI: 10.1111/j.1528-1167.2006.00677.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Idiopathic generalized epilepsy (IGE) accounts for approximately 20% of all epilepsies and affects about 0.2% of the general population. The etiology of IGE is genetically determined, but the complex pattern of inheritance suggests an involvement of a large number of susceptibility genes. The objective of the present study was to explore the genetic architecture of common IGE syndromes and to dissect out susceptibility loci predisposing to absence or myoclonic seizures. METHODS Genome-wide linkage scans were performed in 126 IGE-multiplex families of European origin ascertained through a proband with idiopathic absence epilepsy or juvenile myoclonic epilepsy. Each family had at least two siblings affected by IGE. To search for seizure type-related susceptibility loci, linkage analyses were carried out in family subgroups segregating either typical absence seizures or myoclonic and generalized tonic-clonic seizures on awakening. RESULTS Nonparametric linkage scans revealed evidence for complex and heterogeneous genetic architectures involving linkage signals at 5q34, 6p12, 11q13, 13q22-q31, and 19q13. The signal patterns differed in their composition, depending on the predominant seizure type in the families. CONCLUSIONS Our results are consistent with heterogeneous configurations of susceptibility loci associated with different IGE subtypes. Genetic determinants on 11q13 and 13q22-q31 seem to predispose preferentially to absence seizures, whereas loci on 5q34, 6p12, and 19q13 confer susceptibility to myoclonic and generalized tonic-clonic seizures on awakening.
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MESH Headings
- Chromosome Mapping
- Chromosomes, Human, Pair 11/genetics
- Chromosomes, Human, Pair 13/genetics
- Chromosomes, Human, Pair 19/genetics
- Chromosomes, Human, Pair 5/genetics
- Chromosomes, Human, Pair 6/genetics
- Epilepsies, Myoclonic/genetics
- Epilepsy, Absence/genetics
- Epilepsy, Generalized/genetics
- Genetic Heterogeneity
- Genetic Linkage
- Genetic Predisposition to Disease/genetics
- Humans
- White People/genetics
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Suzuki T, Delgado-Escueta AV, Alonso ME, Morita R, Okamura N, Sugimoto Y, Bai D, Medina MT, Bailey JN, Rasmussen A, Ramos-Peek J, Cordova S, Rubio-Donnadieu F, Ochoa A, Jara-Prado A, Inazawa J, Yamakawa K. Mutation analyses of genes on 6p12-p11 in patients with juvenile myoclonic epilepsy. Neurosci Lett 2006; 405:126-31. [PMID: 16876319 DOI: 10.1016/j.neulet.2006.06.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 06/14/2006] [Accepted: 06/19/2006] [Indexed: 11/30/2022]
Abstract
Juvenile myoclonic epilepsy (JME) is a distinct form of idiopathic generalized epilepsy (IGE). One of the candidate regions for human JME has been mapped on chromosome band 6p11-p12 by linkage analyses and is termed EJM1 (MIM 254770). Recently, we reported the reduction of the EJM1 region to 3.5cM that contains 18 genes, the exclusion of three genes (LRRC1, GCLC, KIAA0057) by mutation analyses, and the identification of Myoclonin1/EFHC1 as the EJM1 gene. Here, we describe detailed physical and transcriptome maps of the 3.5cM EJM1 region, and detailed results of mutation analyses for the remained 14 genes (HELO1, GCMA, KIAA0936, FBXO9, GSTA3, GSTA4, PTD011, KIAA0576, LMPB1, IL17F, MCM3, PKHD1, KIAA0105, TFAP2B) in patients with JME. We identified 49 single nucleotide changes in eight genes. Twelve amino acid substitutions occurred in two genes, 11 silent mutations in seven genes, and 26 in the non-coding or intronic regions of seven genes. Twelve amino acid substitutions in the two genes (IL17F, PKHD1) were also observed in healthy control individuals or did not co-segregate with the disease phenotypes in other family members. Thus, the absence of significant and potentially functional mutations in the remaining 14 genes further supports the concept that Myoclonin1/EFHC1 is the EJM1 gene in chromosome 6p12.
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Affiliation(s)
- Toshimitsu Suzuki
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 Japan
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Millichap JG. Novel Genetic Locus for Generalized Tonic Clonic Epilepsy within the Juvenile Myoclonic Epilepsy Syndrome. Pediatr Neurol Briefs 2005. [DOI: 10.15844/pedneurbriefs-19-9-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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