Abstract

Developmental and epileptic encephalopathies are the most devastating early-onset epilepsies, characterized by early-onset seizures that are often intractable, electroencephalographic abnormalities, developmental delay or regression, and various comorbidities. A large number of underlying genetic variants of developmental and epileptic encephalopathies have been identified over the past few decades. However, the most thorough sequencing studies leave 60–65% of patients without a molecular diagnosis. This review explores the genetic basis of developmental and epileptic encephalopathies that start within the first year of life, including Ohtahara syndrome, early myoclonic encephalopathy, epilepsy of infancy with migrating focal seizures, infantile spasms, and Dravet syndrome. The purpose of this review is to give an overview and encourage the clinicians to start considering genetic testing as an important investigation along with electroencephalogram for better understanding and management of developmental and epileptic encephalopathies.