Perfil clínico e estudo de associação entre polimorfismo SNP 211037 do gene GABRG2 em pacientes com Epilepsia Mioclônica Juvenil provenientes do estado de Alagoas

Abstract

Introduction: Juvenile Myoclonic Epilepsy accounts for 10% of all forms of epilepsy and represents a generalized idiopathic epileptic syndrome with a genetic basis. Despite the existence of rare mutations responsible for some familial forms inherited in a mendelian pattern, the genetics of Juvenile Myoclonic Epilepsy is complex and probably reflect the simultaneous involvement of multiple genes with minor effect and environmental factors. The identification of these susceptibility genes is a great challenge. This case/control study was designed to investigate whether the SNP211037 of GABRG2 gene is a risk factor for juvenile Myoclonic Epilepsy in the north-eastearn Brazilian population. Aims: a) to describe the clinical features of patients with Juvenile Myoclonic Epilepsy selected Clinic at University Hospital of Federal University of Alagoas by the two consultant neurologists; b) to expand the DNA database of Universidade Federal de Alagoas; c) to obtain and evaluate the allelic and genotypic frequencies of SNP211037 in patients with JME and control from the state of Alagoas. Methods: This study included 98 unrelated Brazilian patients with Juvenile Myoclonic Epilepsy and 129 normal control subjects. The probands were unambiguously diagnosed cases of JME with classification based on the published criteria of the Commission on Classification and Terminology of the International League Against Epilepsy. The polymorphism was genotyped using polymerase chain reaction-restriction fragment length polymorphism method. All descriptive and statistical analysis were performed using SNPstat, a web-based tool offered by the Biostatistics and Bioinformatics Unit Web of The Catalan Institute Oncology. Results: The minimum age of patients with Juvenile Myoclonic Epilepsy was 12 years and maximum age of 65. The mean (SD) age at onset of the Juvenile Myoclonic Epilepsy probands was 12,6 years, of which 64% were females. The triad of myoclonus, absences, and generalized tonic-clonic seizures was observed in 59,2%, the combination of myoclonus and generalised tonic-clonic seizures in 37,8%, the combination of myoclonus and absence was observed in 1%, and the myoclonus alone in 2% of patients. No significant differences were observed in the genotype and allele frequencies of this polymorphism between cases and controls. Conclusion: These results present no evidence for an association of SNP211037 with Juvenile Myoclonic Epilepsy. Further studies are required to investigate the involvement of GABRG2 gene in the genetic susceptibility to this epilepsy syndrome.