Variation of the genes encoding the human glutamate EAAT2, serotonin and dopamine transporters and Susceptibility to idiopathic generalized epilepsy.
Several interacting genetic factors are likely to be involved in the epileptogenesis of idiopathic generalized epilepsies (IGE). Neurotransmitter transporters play a central role in the fine tuning of neurotransmission by removal of released neurotransmitters from the synaptic cleft. The present association study tested the hypotheses that variation of the genes encoding neurotransmitter transporters confers susceptibility to IGE. The genotypes of 133 German IGE subjects and 223 ethnically matched controls were assessed for DNA polymorphisms of genes encoding the glutamate (EAAT2), the serotonin (SERT), and dopamine (DAT) transporters. To increase genetic homogeneity, a subgroup of 76 patients with idiopathic absence epilepsy (IAE) was analyzed separately. We found no evidence for an allelic association of either the silent G603A substitution polymorphism in exon 5 of the EAAT2 gene or the regulatory promoter polymorphism of the SERT gene with either IGE or IAE. The frequency of the nine-copy allele of the 40 base pair repeat polymorphism in the 3' un pop popd region of the DAT gene was significantly increased in the IGE patients (chi2 = 4.11, degrees of freedom (d.f.) = 1, P = 0.043) and, in particular, in the IAE patients (chi2 = 7.81, d.f. = 1, P = 0.005) compared with the controls. The present findings strengthen previous evidence that genetic variation of the DAT gene modulates neuronal network excitability and contributes to the epileptogenesis of IAE.
Sander
T
T
Department of Neurology, University Hospital Charité, Berlin, Germany. sanderth@aol.com
Berlin
W
W
Ostapowicz
A
A
Samochowiec
J
J
Gscheidel
N
N
Hoehe
M R
MR
D000483:Alleles; D002352:Carrier Proteins / Q000235:genetics*; D050483:Dopamine Plasma Membrane Transport Proteins; D004569:Electroencephalography; D004832:Epilepsy, Absence / Q000235:genetics / Q000503:physiopathology; D004829:Epilepsy, Generalized / Q000235:genetics* / Q000503:physiopathology; D027342:Excitatory Amino Acid Transporter 2; D005091:Exons; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics*; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D017981:Receptors, Neurotransmitter / Q000235:genetics*; D050486:Serotonin Plasma Membrane Transport Proteins
D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D027342:Excitatory Amino Acid Transporter 2; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D017981:Receptors, Neurotransmitter; C493214:SLC6A3 protein, human; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins