CNKSR2 and Epileptic encephalopathy: CNK2 is a multidomain protein playing vital role in synaptic function.[1,2] The mutation in CNKSR2 leads to a broad spectrum of phenotypic variability and manifests as Houge type of X-linked syndromic mental retardation.[3] Here we report a patient with clinical phenotype including global developmental delay, hyperactivity, severe language impairment, and epileptic encephalopathy caused by a nonsense mutation of CNKSR2 (c.625C > T(p.Gln209∗)).