De novo loss- or gain-of-function mutations in KCNA2 cause epileptic encephalopathy.
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Syrbe S, Hedrich UB, Riesch E, Djemie T, Muller S, Moller RS, Maher B, Hernandez-Hernandez L, Synofzik M, Caglayan HS, Arslan M, Serratosa JM, Nothnagel M, May P, Krause R, Loffler H, Detert K, Dorn T, Vogt H, Kramer G, Schols L, Mullis PE, Linnankivi T, Lehesjoki AE, Sterbova K, Craiu DC, Hoffman-Zacharska D, Korff CM, Weber YG, Steinlin M, Gallati S, Bertsche A, Bernhard MK, Merkenschlager A, Kiess W, Gonzalez M, Zuchner S, Palotie A, Suls A, De Jonghe P, Helbig I, Biskup S, Wolff M, Maljevic S, Schule R, Sisodiya SM, Weckhuysen S, Lerche H, Lemke JR
De novo loss- or gain-of-function mutations in KCNA2 cause epileptic encephalopathy.
Nat Genet. 2015 Apr;47(4):393-9. doi: 10.1038/ng.3239. Epub 2015 Mar 9.
- PubMed ID
- 25751627 [ View in PubMed]
- Abstract
Epileptic encephalopathies are a phenotypically and genetically heterogeneous group of severe epilepsies accompanied by intellectual disability and other neurodevelopmental features. Using next-generation sequencing, we identified four different de novo mutations in KCNA2, encoding the potassium channel KV1.2, in six isolated patients with epileptic encephalopathy (one mutation recurred three times independently). Four individuals presented with febrile and multiple afebrile, often focal seizure types, multifocal epileptiform discharges strongly activated by sleep, mild to moderate intellectual disability, delayed speech development and sometimes ataxia. Functional studies of the two mutations associated with this phenotype showed almost complete loss of function with a dominant-negative effect. Two further individuals presented with a different and more severe epileptic encephalopathy phenotype. They carried mutations inducing a drastic gain-of-function effect leading to permanently open channels. These results establish KCNA2 as a new gene involved in human neurodevelopmental disorders through two different mechanisms, predicting either hyperexcitability or electrical silencing of KV1.2-expressing neurons.