Eight to 20% of individuals with EE‐SWAS, including those with LKS, have been reported to have mutations in GRIN2A,7, 8, 9 encoding the GluN2A subunit of the N‐methyl‐D‐aspartate receptor (NMDAR). This evidence concerns the gene GRIN2A and developmental and/or epileptic encephalopathy with spike-wave activation in sleep.