Role of glyoxalase I gene polymorphisms in late-onset epilepsy and drug-resistant epilepsy.

BACKGROUND: Recent studies indicate that increased expression of glyoxalase I (GLO1) could result in epileptic seizures; thus, this study further explored the association of GLO1 with epilepsy from the perspective of molecular genetics. MATERIAL AND METHODS: GLO1 single nucleotide polymorphisms (SNPs; rs1130534, rs4746 and rs1049346) were investigated in cohort I (the initial samples: 249 cases and 289 controls). A replication study designed to confirm the positive findings in cohort I was performed in cohorts II (the additional samples: 130 cases and 191 controls) and I+II. RESULTS: In cohorts I, II and I+II, the CC genotype at rs1049346 T>C exerts a protective effect against both late-onset epilepsy (odds ratio [OR]=2.437, p=0.013; OR=2.844, p=0.008; OR=2.645, p=0.000, q=0.003, respectively) and drug-resistant epilepsy (DRE) (OR=2.985, p=0.020; OR=2.943, p=0.014; OR=3.049, p=0.001, q=0.006, respectively). Further analyses in cohort I+II indicate that the presence of the TAC/AAT haplotypes (rs1130534-rs4746-rs1049346) may be used as a marker of predisposition to/protection against DRE (p=0.002, q=0.010; p=0.000, q=0.002, respectively). CONCLUSIONS: This study is the first to demonstrate that the GLO1 SNPs are significantly associated with epilepsy. In particular, the rs1049346 T>C SNPs are potentially useful for risk assessment of late-onset epilepsy and DRE.

Association of Tag SNPs and Rare CNVs of the MIR155HG/miR-155 Gene with Epilepsy in the Chinese Han Population.

BACKGROUND: miR-155 likely acts as an important modulator in the inflammatory mechanism of epilepsy, and this study investigated its association with epilepsy from the perspective of molecular genetics. METHODS: This study enrolled 249 epileptic patients and 289 healthy individuals of the Chinese Han population; 4 tag single-nucleotide polymorphisms (SNPs: rs969885, rs12483428, rs987195, and rs4817027) of the MIR155HG/miR-155 gene were selected, and their association with epilepsy was investigated. Additionally, this study determined the copy numbers of the MIR155HG/miR-155 gene. RESULTS: The TCA haplotype (rs12483428-rs987195-rs4817027) and the AA genotype at rs4817027 conferred higher vulnerability to epilepsy in males. Stratification by age of onset revealed that the CC haplotype (rs969885-rs987195) was a genetic susceptibility factor for early-onset epilepsy. Further stratification by drug-resistant status indicated the CC haplotype (rs969885-rs987195) and the AA genotype at rs4817027 were genetic susceptibility factors for drug-resistant epilepsy (DRE) but the CG haplotype (rs987195-rs969885) was a genetically protective factor against DRE. Besides, 3 epileptic patients with copy number variants of the MIR155HG/miR-155 gene were observed. CONCLUSIONS: This study first demonstrates the association of MIR155HG/miR-155 tag SNPs with epilepsy and shows that rare CNVs were found exclusively in epileptic patients, clarifying the genetic role of miR-155 in epilepsy.

Association of KEAP1 and NFE2L2 polymorphisms with temporal lobe epilepsy and drug resistant epilepsy.

BACKGROUND AND AIMS: Temporal lobe epilepsy (TLE) is a prevalent form of epilepsy. TLE contributes to the majority of drug resistant epilepsy (DRE) cases and is associated with genetic factors. Kelch-like ECH-associated protein 1 (KEAP1)/Nuclear erythroid 2-related factor 2 (known as NFE2L2 or Nrf2) association has been implicated in neuroprotection due to induction of antioxidant enzymes. The association of one single KEAP1 gene nucleotide polymorphism (SNP) and nine NFE2L2 gene SNPs with TLE and DRE were examined to determine whether these SNPs influenced the risk of TLE and DRE in a Han population. SUBJECTS AND METHODS: A total of 184 TLE patients (including 72 DRE patients) and 183 controls were included in this analysis. The SNaPshot Multiplex kit was used to assess the genotypes. RESULTS: A NFE2L2 gene haplotype was identified as a risk factor for TLE (OR=7.11, 95% CI 1.53-32.98). Additionally, rs2706110 G>A in the NFE2L2 gene and rs1048290 C>G in the KEAP1 gene showed a significant risk for and a protective effect against DRE, respectively. CONCLUSION: Our findings suggest that variations in NFE2L2 gene increase the risk of TLE and DRE but that variations in KEAP1 gene play a protective role for DRE.

A functional polymorphism of the microRNA-146a gene is associated with susceptibility to drug-resistant epilepsy and seizures frequency.

PURPOSE: Epilepsy is the third most common chronic brain disorder and is characterized by an enduring predisposition for seizures. Recently, a growing body of evidence has suggested that microRNA-146a (miR-146a) is upregulated in the brains of epilepsy patients and of mouse models; furthermore, miR-146a may be involved in the development and progression of seizures through the regulation of inflammation and immune responses. In this report, we performed a case-control study to analyze the relationship between the two potentially functional single nucleotide polymorphisms (SNPs) of the miR-146a gene (rs2910464 and rs57095329) and the risk of epilepsy in a Chinese population comprising 249 cases and 249 healthy controls. METHOD: Our study comprised 249 epilepsy patients and 249 healthy controls in two regions of China. The DNA was genotyped using the ABI PRISM SNapShot method. The statistical analysis was estimated using the chi-square test or Fisher's exact test. RESULTS: Our results indicated a significant association between the rs57095329 SNP of the miR-146a gene and the risk of drug resistant epilepsy (DRE) (genotypes, p = 0.0258 and alleles, p = 0.0108). Moreover, the rs57095329 A allele was found to be associated with a reduced risk of seizures frequency in DRE patients (all p < 0.001). However, the rs2910164 variant was not associated with epilepsy. CONCLUSION: Our data indicate that the rs57095329 polymorphism in the promoter region of miR-146a is involved in the genetic susceptibility to DRE and the seizures frequency.