Kv2.1 mutations have been linked to a range of severe neurological outcomes including epileptic encephalopathy, developmental delay, intellectual disability, and autism (24, 25, 26, 27, 28), whereas Kv2.2 mutations have been recently linked to neurodevelopmental delay accompanied by anatomical abnormalities (29). This evidence concerns the gene KCNB2 and Neurodevelopmental delay.