DNM1 encephalopathy – interneurons, endocytosis, and study group

Dynamin 1. De novo mutations in DNM1 coding for Dynamin 1 are increasingly recognized as a cause for epileptic encephalopathies. However, given the role of Dynamin 1 in endocytosis in a large number of cells, the precise mechanisms how mutations may result in seizures are poorly understood. Now two recent publications in PLOS Genetics and Neurology Genetics explore the functional effects of epilepsy-related DNM1 mutations. The publication of both manuscripts is also a timely reminder to announce our international DNM1 study group that has the aim to better understand the phenotype of this disease. Continue reading

Exomes on the go – adventures with wANNOVAR

Going cloud. This post is about my most recent discovery when I was trying to modernize some of the bioinformatics tools that I had on my laptop. My experience with variant annotation is a good example of the latest trend in bioinformatics: replacing precise, but difficult-to-use tools by web-based convenience – I didn’t need to install anything after all. This is a brief journey into the world of variant annotation, taking advantage of my new favorite tool, wANNOVAR and applying it to the Epi4K dataset. Continue reading

Launching the Epilepsy Genetics Initiative – Go EGI!

Launch. This week, the Epilepsy Genetics Initiative (EGI) was launched. EGI was founded by Citizens United for Research in Epilepsy (CURE) and represents a large database for diagnostic and research exomes that will guarantee regular re-analysis of exome data, which is particularly relevant for the large number of exomes that we think are negative. Here is a brief blog post why all exomes should eventually find their way into EGI. Continue reading

Cause or coincidence – recessive SCN1A variants in Dravet Syndrome

Recessive epilepsies. Dravet Syndrome is one of the most prominent genetic epilepsies and presents in the first year of life with prolonged fever-associated seizures. Haploinsufficiency of SCN1A, either through mutations or deletions, is the major cause of Dravet Syndrome. In a recent publication in the European Journal of Pediatric Neurology, two families with recessive Dravet Syndrome and biallelic SCN1A variants are reported. Let’s have a look at how to interpret these findings. Continue reading

Publications of the week – Dravet Syndrome, TBC1D24, and CSTB

Issue 6/2015. Publications from the most recent issue of Epilepsia are very prominent in this week’s selection of publications. We discuss the frequency of Dravet Syndrome, a novel family with a TBC1D24 mutation, and the role of Cystatin B (CSTB) in Juvenile Myoclonic Epilepsy. Continue reading

Beyond SCN1A – Copy Number Variations in fever-associated epilepsies

Fever and epilepsy. When it comes to epilepsy and fever, either Febrile Seizures or Dravet Syndrome are usually the most prominent topics on our blog. However, in addition to these syndromes, there various other epilepsies that have fever-related seizures as a prominent feature. In a recent publication in Epilepsia, we investigated the role of microdeletions in a group of patients with prominent fever-associated epilepsies. Our findings suggest that fever-associated epilepsy syndromes may be a presentation of known microdeletion syndromes. Continue reading

Sequencing for developmental disorders on a national level – the DDD(UK) study

DDD. It’s probably the most impressive of all exome sequencing studies of 2014 and I almost missed it. Late December last year, the Deciphering Developmental Disorders study was published in Nature, reporting the genetic findings in more than 1,000 patient-parent trios, which were collected in a systematic nation-wide approach in the United Kingdom and Ireland. The analysis of more than 1,600 de novo mutations in this cohort provides another fascinating view into the genetics of neurodevelopmental disorders, independently confirming the role of DNM1 and pointing out several genes that act through either activating or dominant-negative mutations. Let me guide you through a study that comes to the sobering conclusion that even entire nations are too small to understand the genetics of neurodevelopmental disease. Continue reading

SCN8A encephalopathy – and how it differs from Dravet Syndrome

Nav1.6. For some reason, SCN8A always met some resistance. In contrast to other epilepsy genes, it took a while for the community to embrace this gene as a genuine cause of epileptic encephalopathies. A recent publication in Neurology now investigates the phenotypic spectrum of SCN8A encephalopathy – and points out important features that distinguish this condition from Dravet Syndrome. Continue reading

These are the top 10 epilepsy genes of 2014

Top 10. 2014 has been a very productive year in epilepsy gene discovery and with our final blog post this year, we wanted to provide a brief overview of what has been pertinent this year. From the multitude of novel genes identified this year, here are the 10 most relevant findings – including some genes that you probably didn’t expect. Continue reading

Heat at the synapse – STX1B mutations in fever-associated epilepsies

Febrile Seizures. The discovery of the genes for fever-associated epilepsies was one of the most relevant milestones in epilepsy genetics. Discovery of the underlying genes including SCN1A, SCN1B and GABRG2 was tightly linked to the development of the Genetic/Generalized Epilepsy with Febrile Seizures Plus (GEFS+) concept, describing the spectrum of epilepsy phenotypes seen in families with these mutations. Gene discovery in GEFS+, however, has slowed down in recent years, and no further causative genes had been identified for more than a decade. Now, in a recent paper in Nature Genetics, mutations in STX1B are found as a novel cause for fever-associated epilepsies. Continue reading