The two faces of KCNA2 – a novel epileptic encephalopathy

Delayed rectifier. The discovery of de novo mutations in ion channel genes as a cause for genetic epilepsies continues. In a recent publication in Nature Genetics, we have identified de novo mutations in KCNA2 as a novel cause of epileptic encephalopathies associated with ataxia. Interestingly, even within a single gene, two different phenotypes seem to be emerging. Continue reading

Twisting DNA and seizures: TDP2 mutations in neurodegeneration with epilepsy

Torsional stress. The DNA double helix has one major problem that we know from telephone cords: it is difficult to untangle. However, our DNA is constantly twisted and untangled for gene transcription. This constant twisting and untwisting produces torsional stress that is relieved by topoisomerases. A recent publication in Nature Genetics now identified a human neurological phenotype that is caused by faulty activity of this mechanism: neurodegeneration with epileptic encephalopathy. However, there are some features of the phenotype that are not easily explained by erroneous DNA twisting. Continue reading

GOSR2, North Sea myoclonus and the Haithabu variant

Wall Street. Between the 8th and 11th century, Haithabu (Hebedy), a Viking town in Northern Germany close to the border to Denmark was the Manhattan of its time – a flourishing trading town located at a busy shipping route at a natural short passage connecting the Eider and the Treene river, a precursor of the modern-day Kiel canal. The  Vikings used this shortcut to avoid the dangerous Skagerak when heading West on their conquests. When subsequently settling down in many regions of the North Sea coast, they carried their genetic heritage with them, including a rare variant in the GOSR2 gene, which results in a devastating epilepsy when homozygous. A recent paper in Brain now delineates the phenotype of the “North Sea” progressive myoclonus epilepsy. Continue reading