One of the identified pathogenic GRIN2A mutations-de novo c.2094T>G (p.Y698*) has not been reported before, whereas the GRIN2A mutation-de novo c.2041C>T (p.Y681*) has been reported in a family with LKS in 2013 (inherited). Here, GRIN2A is linked to developmental and/or epileptic encephalopathy with spike-wave activation in sleep.