May 14, 2015: KCNQ2 in early onset epileptic encephalopathy

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May 14, 2015

KCNQ2 in early onset epileptic encephalopathy

Early cognitive dysfunction and refractory epilepsy are characteristic of early onset epileptic encephalopathy (EOEE). A clear understanding and recognition of children with early onset epileptic encephalopathy is crucial to timely diagnosis and initiation of treatment. Syndromes such as Otahara Syndrome, West Syndrome, myoclonic encephalopathy, and Dravet Syndrome are all well studied with known genetic mutations. Mutation of the KCNQ2 gene leads to impaired production of the potassium channel subunit Kv7.2. KCNQ2 mutations have been recognized in benign familial neonatal epilepsy. However, de novo mutations can be seen in early onset epileptic encephalopathy. A burst suppression pattern is characteristic on EEG. Seizures are often tonic in nature and patients have a severe intellectual disability. Missense mutations are most common in early onset epileptic encephalopathy with KCNQ2 mutations, with frameshift and nonsense mutations more common in benign familial neonatal seizures. Imaging may show hyperintense lesions of the globus pallidus on MRI imaging.


  1. Borgatti R, Zucca C, Cavallini A, et al. A novel mutation in KCNQ2 associated with BFNC, drug resistant epilepsy, and mental retardation. Neurology 2004; 63: 57–65.
  2. Kato M, Yamagata T, Kubota M, et al. Clinical spectrum of early onset epileptic encephalopathies caused by KCNQ2 mutation. Epilepsia 2013; 54:1282–1287.

Submitted by James Addington, M.D. Resident Physician, Department of Neurology, University of Virginia

Disclosures: Dr. Addington is a member of the Residents & Fellows Section of Neurology.

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