Asunto(s)
Proteínas de Transporte de Glutamato en la Membrana Plasmática/genética , Enfermedad de Parkinson/genética , Polimorfismo de Nucleótido Simple/genética , Temblor Esencial/genética , Transportador 2 de Aminoácidos Excitadores , Femenino , Estudios de Asociación Genética , Alemania , Humanos , Masculino , Estados UnidosRESUMEN
OBJECTIVE: Sporadic, genetically complex essential tremor (ET) is one of the most common movement disorders and may lead to severe impairment of the quality of life. Despite high heritability, the genetic determinants of ET are largely unknown. We performed the second genome-wide association study (GWAS) for ET to elucidate genetic risk factors of ET. METHODS: Using the Affymetrix Genome-Wide SNP Array 6.0 (1000K) we conducted a two-stage GWAS in a total of 990 subjects and 1,537 control subjects from Europe to identify genetic variants associated with ET. RESULTS: We discovered association of an intronic variant of the main glial glutamate transporter (SLC1A2) gene with ET in the first-stage sample (rs3794087, p = 6.95 × 10(-5), odds ratio [OR] = 1.46). We verified the association of rs3794087 with ET in a second-stage sample (p = 1.25 × 10(-3), OR = 1.38). In the subgroup analysis of patients classified as definite ET, rs3794087 obtained genome-wide significance (p = 3.44 × 10(-10), OR = 1.59) in the combined first- and second-stage sample. Genetic fine mapping using nonsynonymous single nucleotide polymorphisms (SNPs) and SNPs in high linkage disequilibrium with rs3794087 did not reveal any SNP with a stronger association with ET than rs3794087. CONCLUSIONS: We identified SLC1A2 encoding the major glial high-affinity glutamate reuptake transporter in the brain as a potential ET susceptibility gene. Acute and chronic glutamatergic overexcitation is implied in the pathogenesis of ET. SLC1A2 is therefore a good functional candidate gene for ET.
Asunto(s)
Temblor Esencial/genética , Proteínas de Transporte de Glutamato en la Membrana Plasmática/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Intervalos de Confianza , Transportador 2 de Aminoácidos Excitadores , Femenino , Frecuencia de los Genes , Estudio de Asociación del Genoma Completo , Genotipo , Alemania , Humanos , Desequilibrio de Ligamiento , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Control de Calidad , Población Blanca , Adulto JovenRESUMEN
Essential tremor (ET) and Parkinson's disease (PD) are the most common movement disorders and show clinical, genetic, and pathophysiological overlap. Single-nucleotide polymorphisms (SNPs) in the leucine-rich repeat (LRR) and immunoglobulin (Ig) domain-containing, Nogo receptor-interacting protein gene (LINGO1) are associated with ET. LINGO1 is overexpressed in the substantia nigra (SN) of PD patients and inhibition of LINGO1 confers neuroprotection in a rodent model of PD. In this study we test the hypothesis whether SNPs in the LINGO1 gene that are associated with ET are also associated with PD. Three large German case-control samples from Kiel, Lübeck, and Tübingen (total: 1,798 cases and 1,482 controls) were genotyped for the three LINGO1 SNPs associated with ET. Association was assessed using allele- and genotype-based tests in each of the three samples separately, in the combined sample, and in subsets of patients with early-onset PD (<50 years) and of patients with a positive family history of PD. Neither of the three samples alone nor the combined sample showed evidence for association between LINGO1 SNPs and PD. The allele-based test showed a trend toward nominal association for all three SNPs in the Kiel sample. The subsets with early-onset PD or a positive family history did also not reveal evidence for association. SNPs in the LINGO1 gene associated with ET could not be shown to be associated with PD in our study population, despite a postulated overlap between both diseases.
Asunto(s)
Proteínas de la Membrana/genética , Proteínas del Tejido Nervioso/genética , Enfermedad de Parkinson/genética , Polimorfismo de Nucleótido Simple/genética , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Femenino , Estudio de Asociación del Genoma Completo , Genotipo , Alemania , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/etnología , Adulto JovenRESUMEN
Essential tremor (ET) is one of the most common movement disorders. Former association studies focussing on candidate genes in ET found a number of risk variants but most of them were not replicated. Recently, a genome-wide association study revealed two intronic sequence variants in the LINGO1 gene associated with ET. Here, we have confirmed association between sequence variants in the LINGO1 gene and the ET phenotype in independent German and French ET samples. The odds ratios for the identified intronic markers rs8030859 (P = 1.0x10(-4)), rs9652490 (P = 9.1x10(-4)), and rs11856808 (P = 3.6x10(-2)) were 1.72 (CI 1.31-2.26), 1.61 (CI 1.21-2.14), and 1.30 (CI 1.02-1.66), respectively, in our German sample. LINGO1 is an interesting candidate gene because it plays a key role in central nervous system biology, is selectively expressed in the nervous system, and is an inhibitor of oligodendrocyte differentiation and neuronal myelination. Our study gives further evidence that LINGO1 acts as a susceptibility gene for ET.
Asunto(s)
Temblor Esencial/genética , Predisposición Genética a la Enfermedad , Proteínas de la Membrana/genética , Proteínas del Tejido Nervioso/genética , Polimorfismo de Nucleótido Simple/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Distribución de Chi-Cuadrado , Temblor Esencial/epidemiología , Europa (Continente)/epidemiología , Femenino , Frecuencia de los Genes , Estudio de Asociación del Genoma Completo/métodos , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
The genetic causes of essential tremor (ET) seem to be heterogeneous. Recently, ET has been found associated with a functional variant (Ser9Gly) of the dopamine D(3) receptor (DRD3), located in the ETM1 locus on chromosome 3q13.3 described for the first time in 1997. We examined this variant in three different populations from Germany, Denmark and France. We undertook an association study of the Ser9Gly variant in 202 cases with a familial history from unrelated families with ET, 97 cases with isolated non-familial ET and 528 healthy controls. In addition, linkage and segregation analyses were carried out in 22 ET families. The distribution of genotypes and allele frequencies showed no significant differences in the whole sample and in a subanalysis of familial and sporadic cases. Age at onset of tremor, tremor duration and tremor severity did not show an association with the genotype. In addition, the DRD3 variant was not found linked to the disease in a subset of informative ET families. We did not find a significant association of the DRD3 variant with ET nor linkage to the DRD3 receptor in German, Danish and French ET patients and families, suggesting that it is unlikely to be a causal factor for ET.