Genetic epileptic encephalopathies

Epileptic encephalopathies are characterized by early seizure onset or EEG abnormalities, leading to increasing brain dysfunction. They often consist of early-onset and pharmacoresistant epilepsies, including well-defined electro-clinical syndromes such as West syndrome or Lennox–Gastaut syndrome. In many cases of clinical routine, assignment to one of these defined syndromes is not possible. These cases of “non-classical” epileptic encephalopathy often show a certain overlap with the classical syndromes, but display additional distinct features. In addition to structural and metabolic causes, over the last few years numerous new genetic mutations have constituted the main etiology of this disease group. Knowledge about the genetic heterogeneity of this disease group has thereby grown exponentially, revealing the functional similarities of the causative genes. Different genes may cause similar conditions and, vice versa, mutations of the same gene may lead to widely differing phenotypes. To deal with this steadily growing complexity in clinical routine, gene panel analysis in particular provides a fast and efficient method. The establishment of a genetic diagnosis can prevent ongoing, possibly harmful or distressing diagnostic tests, allows genetic and prognostic counseling, and increasingly offers opportunities for targeted treatment. This review provides an overview of the main epileptic encephalopathies and the corresponding genetic mutations. © 2015, Springer-Verlag Berlin Heidelberg.