Publications of the week – DOCK7, DEPDC5 and the yield of diagnostic gene panels

This week in epilepsy genetics. The following publications are a selection of what was published in the last week. These studies might be relevant for you because they both extend the phenotype of recent gene findings and describe novel genes that you should be aware of. Continue reading

2013 in review: top three lists and the gene finding of the year

Gene of the year. Let’s take a minute to look back at the very busy year of 2013. There were major advances in many areas of epilepsy genetics. First and foremost, massive (and I mean massive) progress has been made in the genetics of the epileptic encephalopathies, where de novo mutations have been identified as a major source of genetic morbidity. Secondly, the new technologies have made it possible to identify several novel genes for various epilepsy types. Out of these genes, we have again selected the most important finding in 2013. And the gene finding of the year is… Continue reading

Guilt by association: SCN1A in Temporal Lobe Epilepsy

GWAS. Genome-wide association studies investigate the association of common genetic variants with disease in large patient samples. While this approach has been very successful in many other diseases, the results in epilepsy research have been less convincing. Given the complexity of epilepsy phenotypes, selection of the right epilepsy phenotype has been an ongoing debate. Now, a recent study in Brain finds an intronic variant of the SCN1A gene that is associated with Temporal Lobe Epilepsy (TLE), the most common epilepsy in man. Interestingly, the association with SCN1A seems to be specific for only a particular subtype of focal epilepsies. Continue reading

Thalamus, timing and TSC1 deletions

Tuberous Sclerosis. Tuberous Sclerosis Complex (TSC) is a neurodevelopmental disorder caused by lack of function of the TSC1 or TSC2 tumor suppressor gene. With respect to the Central Nervous System, this disease is characterized by so-called tubers, benign tumors consisting of dysplastic neurons that are highly epileptogenic. Accordingly, TSC is one of the most common causes of West Syndrome. However, there is also evidence for neurological dysfunction beyond tubers. Increasing evidence suggests that the mutations alone can result in abnormalities of neuronal networks, resulting in epilepsy, intellectual disability or autism. The thalamus appears to be a key structure that is affected by this dysfunction. Now, a recent study in Cell explores the effects of TSC1 deletions at different developmental stages with respect to neuronal development in the thalamus. Continue reading

DEPDC5, meet the mTOR pathway – a novel mechanism in genetic focal epilepsies

Variable foci. A few weeks ago, we discussed the recent gene finding in Familial Partial Epilepsy with Variable Foci, a rare but puzzling familial epilepsy syndrome. DEPDC5 was identified as the culprit gene. However, the potential function of the gene product left researcher scratching their heads. Now, a recent paper in Science suggests that DEPDC5 might interact with the mTOR pathway, the master regulator of growth. Should we reconsider the role of the mTOR pathway in genetic focal epilepsies? Continue reading

Familial Partial Epilepsy with Variable Foci and mutations in DEPDC5

A long story, a complicated phenotype. Massive parallel sequencing technologies were an innovation in neurogenetics and made the discovery of many genes underlying familial epilepsies possible. However, some epilepsy syndromes turned out to be more “stubborn” than others. Now, in a back-to-back submission in Nature Genetics, two groups report on the gene underlying Familial Partial Epilepsy with Variable Foci (FPEVF). And no, it’s not an ion channel this time. Continue reading