Trio exomes. The concept of neurodevelopmental disorders is an umbrella term including intellectual disability, developmental delay, and autism spectrum disorder. About one quarter of these patients have epilepsy, including epileptic encephalopathy, in which the epileptic activity itself contributes to developmental delay or regression. One major cause of these disorders are de novomutations, which are present in the child but not present in either of the parents. A recent publication in Nature Genetics looked for de novo variants in nearly 6,700 patients with neurodevelopmental disorders, nearly 2,000 of whom had epilepsy. This study is an order of magnitude larger than the largest previous study of this kind and represents an important effort in epilepsy genetics. Here is what we want to review their major findings. Continue reading →