Desert Dessert. Cold temperatures, streets closed because of snow – this is not what you expect when traveling to Israel. You also do not expect to have the chance to taste traditional Bedouin food and to see a beautiful canyon every morning. The biggest surprise is that you do not expect this during a workshop. From Dec 12-15th, the European epilepsy genetic community gathered in Be’er Sheva and Sde Boker, Israel for a combined epilepsy genetics workshop and a Young Researcher Meeting. This is a brief attempt to capture the atmosphere of this workshop for everybody who could not attend. By the way, “desert dessert” is a port wine produced in the Negev desert.
Year of the glutamate receptor. A few months ago we wrote a post about the triplet of Nature Genetics publications that established GRIN2A mutations as a cause of disorders within the epilepsy aphasia spectrum. GRIN2A codes for the NR2A subunit of the NMDA receptor, one of the most prominent neurotransmitter receptors in the Central Nervous System. Now, a recent paper in the Annals of Neurology reports mutations in the GRIN2B subunit as a cause of Infantile Spasms. Interestingly, the functional consequences of these mutations are completely different from GRIN2A-related epilepsies. Continue reading
Complexity. Structural genomic variants or copy number variations (CNV) are known genetic risk factors for various epilepsy syndromes. In fact, CNVs might represent the single most studied type of genetic alterations across a very broad range of epilepsy syndromes. There is, however, a group of patients that is usually not investigated in genetic studies: patients with presumable lesional epilepsies or questionable findings on Magnetic Resonance Imaging (MRI). Many of these epilepsies are usually thought to be secondary to the identified lesion, and genetic risk factors are not considered. In a recent study in the European Journal of Human Genetics last week, we investigated the role of CNVs in a cohort of patients with complex epilepsy phenotypes that were not easily classified into existing categories. Many of patients included had definite or questionable findings on MRI. The results of our study made us wonder whether the boundary between lesional and genetic epilepsies needs to redrawn. Continue reading
Joining forces. The EuroEPINOMICS-RES consortium and Epi4K/EPGP are currently joining forces for genetic studies on epileptic encephalopathies. A first collaborative study focuses on de novo mutations in Infantile Spasms and Lennox-Gastaut-Syndrome. In the last two years, after decades of disappointment, we have finally managed to accomplish a breakthrough in understanding the genetic basis of epileptic encephalopathies. The method of trio-based exome sequencing works amazingly well to identify the genetic cause, and the field currently has the crucial momentum to reach the next level of research. Let’s briefly review why we need international collaborations to disentangle the genetic architecture of the epileptic encephalopathies. Continue reading
What has become of that simple 21,000-gene genome of ours? Today even the definition of gene is no longer clear. What biotypes belong to lncRNAs and what’s the job of unitary pseudogenes? For geneticists dog-paddling in complex diseases another surprise came last year with the announcement that roughly 80% of the genome has some sort of function. Confused? Grab this issue of Genome Research and read the review by Mudge and colleagues, who discuss many examples of the transcriptional complexity within the human genome. Continue reading
The two faces of SCN1A. Even though the range of phenotypes associated with mutations in SCN1A can be conceptualized as a continuum, there are usually two distinct entities in clinical practice: the severe, epileptic encephalopathy of Dravet Syndrome due to de novo mutations and the usually mild fever-related epilepsies in autosomal dominant GEFS+ families. While Dravet Syndrome can also be seen in some families with Genetic Epilepsy with Febrile Seizures Plus (GEFS+), this is a rare phenomenon; there is usually little overlap between Dravet Syndrome and GEFS+. Within the Israel Epilepsy Family Project, we came across such a family with overlapping phenotypes. This recently published large GEFS+ family probably has the widest phenotypic range reported to date. Continue reading
Postsynaptic. SHANK proteins are elements of the postsynaptic density, linking synaptic transmission with the cytoskeleton. Deletions in SHANK2 and SHANK3 are known genetic risk factors for a broad range of neurodevelopmental disorders. The role of the reciprocal duplications, however, has remained unclear. In recent paper in Nature, a novel mouse model expressing a SHANK3 transgene is investigated. The results of a mere 1.5 fold overexpression of the protein are dramatic, hinting at unanticipated mechanisms that regulate the balance between excitation and inhibition. Continue reading
My name is Dennis Lal, I am working on the genetics of rolandic epilepsy and idiopathic generalized epilepsies within the EuroEPINOMICS consortium. Like many scientists, I read a lot of publications, or well, at least the abstract. Roland and Ingo asked me repeatedly to write a post but I was afraid of losing too much time. But as a young and naive scientist you have to give things a try.That’s why I started commenting on my favorite papers of the week, collected here. This “experiment” is currently at 35 minutes (after several rounds of editing) and I aim to finish this blog post below 60 minutes.
What is epigenetics? In a single idea: the molecular memory of a cell. The system stores information of previously external (e.g. environmental) or internal (e.g. developmental) stimuli, learns from this experience and responds. A collection of specific tags tells genes whether to be ON or OFF. Hardcore epigeneticists claim that an epigenetic tag should be meiotically and/or mitotically heritable, self-perpetuating, and reversible. DNA methylation is the mechanism coming closest to this ideal. A more liberal definition not focusing on heritability refers to any structural adaptation of the chromatin template that regulates gene expression. This would also include posttranslational histone tail modifications, incorporation of histone variants, chromatin remodeling processes, and action of non-coding RNAs. The large variety, flexibility, interdependence and potential synergistic effects of epigenetic mechanisms could provide the molecular basis for any phenotypic variation in physiological and pathological conditions. In epilepsy research this is especially interesting with regard to the stimulus-driven activity and connectivity of post-mitotic neurons in the adult brain. We set out to study methylation for the most common form of epilepsy in adults. Continue reading
Heathrow. Dark social? Threat? I’ll get back to that. I am writing this wrap-up post for the SpotOn 2013 meeting overlooking the British Airways planes on their way to take-off. In the last two days, we caught a glimpse of what online science communication is about. On Saturday, we had our own session #solo13blogs on using blogs for peer-to-peer science communication. As a science communication newbie, I am happy that our session was well received and stimulated quite some discussion. I have taken away three things from this meeting – a new understanding of our readership, an appreciation for Open Access and data sharing, and finally, a fear of the destructive power of dark social that also applies to epilepsy genetics research. But first things first. Continue reading