RESUMO
The Krebs cycle is of fundamental importance for the generation of the energetic and molecular needs of both prokaryotic and eukaryotic cells. Both enantiomers of metabolite 2-hydroxyglutarate are directly linked to this pivotal biochemical pathway and are found elevated not only in several cancers, but also in different variants of the neurometabolic disease 2-hydroxyglutaric aciduria. Recently we showed that cancer-associated IDH2 germline mutations cause one variant of 2-hydroxyglutaric aciduria. Complementary to these findings, we now report recessive mutations in SLC25A1, the mitochondrial citrate carrier, in 12 out of 12 individuals with combined D-2- and L-2-hydroxyglutaric aciduria. Impaired mitochondrial citrate efflux, demonstrated by stable isotope labeling experiments and the absence of SLC25A1 in fibroblasts harboring certain mutations, suggest that SLC25A1 deficiency is pathogenic. Our results identify defects in SLC25A1 as a cause of combined D-2- and L-2-hydroxyglutaric aciduria.
Assuntos
Proteínas de Transporte de Ânions/genética , Encefalopatias Metabólicas Congênitas/etiologia , Ácido Cítrico/metabolismo , Genes Recessivos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Mutação/genética , Sequência de Aminoácidos , Biomarcadores/análise , Encefalopatias Metabólicas Congênitas/metabolismo , Encefalopatias Metabólicas Congênitas/patologia , Estudos de Casos e Controles , Células Cultivadas , Cromatografia Líquida , Exoma/genética , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Glutaratos/urina , Humanos , Masculino , Dados de Sequência Molecular , Transportadores de Ânions Orgânicos , Fenótipo , Estrutura Terciária de Proteína , Estudos Retrospectivos , Homologia de Sequência de Aminoácidos , Estereoisomerismo , Espectrometria de Massas em TandemRESUMO
Vagus nerve stimulation (VNS) is an additive treatment option for refractory epilepsy. The electrode is placed on the cervical trunk of the left vagus nerve. In patients who are not suitable for left-sided vagus nerve stimulation (L-VNS) right-sided vagus nerve stimulation (R-VNS) may be as effective. In animal models epilepsy is sufficiently suppressed by R-VNS. In a 16 years old boy suffering from medically refractory psychomotoric seizures with secondary generalisation, L-VNS reduced the frequency of generalized seizures. A deep wound infection required the removal of the system eight weeks later. Cicatrisation did not allow preparation of the left vagus nerve, therefore we implanted R-VNS with sufficient seizure suppression. However, compared to L-VNS, the effect occurred months later and cardiac symptoms were induced by stimulation of the right vagus nerve. R-VNS seems to be an effective and alternative therapy in selected patients responding to L-VNS where a left-sided reimplantation is not possible. Placement and adjustment of the device should be performed under ECG control. Further studies are necessary to compare the efficacy of L-VNS and R-VNS.
