EIEE1-19. Online Mendelian Inheritance in Man (OMIM) is one of the most frequently accessed online databases for information on genetic disorders. Genes for epileptic encephalopathies are organized within a phenotypic series entitled Early Infantile Epileptic Encephalopathy (EIEE). The EIEE phenotypic series currently lists 19 genes (EIEE1-19). Let’s review the evidence for these genes as of 2014. Continue reading
Category Archives: EuroEPINOMICS
The final EuroEPINOMICS General Assembly – Impressions from Helsinki
Time flies by. Last week, we have had the final General Assembly of the EuroEPINOMICS project in Tuusula, Finland. All four projects of the EuroEPINOMICS consortium presented the current, ongoing projects and it’s good to hear that there are multiple publications in various stages coming up. Over the three years of the consortium, the diverse groups grew closer together. During this meeting many unpublished results were shown, including extension of studies on genes such as HCN1, CHD2, GRIN2A, GRIN2B or RBFOX1 as well as more data on epigenetics in acquired epilepsy.
The return of the h-current: HCN1 mutations in atypical Dravet Syndrome
Hyperpolarization. More than a quarter of a century ago, physiologists identified an electrical current in neurons and cardiac myocytes that behaved so strangely that it was called the “queer” or “funny” current: it paradoxically caused depolarization upon hyperpolarization. This current was finally named h-current and is mediated by HCN channels. The h-current has been associated with epilepsy through functional studies, but a genetic link has been elusive so far. In a recent publication in Nature Genetics, de novo mutations in HCN1 are identified in patients with early-onset epileptic encephalopathies resembling Dravet Syndrome. Continue reading
The genetic architecture toolkit – modeling polygenic disease with rare variants
Architecture. Even though we often write about novel gene findings in the epilepsies, we assume that most epilepsies are complex genetic or polygenic. Polygenic inheritance suggests the genetic architecture is composed of multiple interacting genetic risk factors, each contributing a small proportion to the disease risk. However, when using the phrase genetic architecture, sometimes I am not quite sure what I actually mean by this. For example, how many genes are needed? This is why I wanted to build a model genetic architecture and explore what happens if we build a genetic disease solely from rare risk variants. Follow me to a brief back-of-the-envelope calculation of how this might work.
A look back at the Leuven NGS bioinformatics meeting
Program completed. On Sunday, we finished our EuroEPINOMICS next generation sequencing (NGS) bioinformatics meeting. After working through the command line, running scripts, and staring at black screens with white cursors, we completed our four day course by looking at the more user friendly, web-based tools that the NGS world has to offer, including Galaxy, Varbank, and Ingenuity. I think it was the general consensus among the participants that this was the bioinformatics meeting that we needed in order to understand the data that we generate and deal with on day-to-day basis. These were my favorite sound bites of our meeting. Continue reading
9 things you didn’t know about bioinformatics
Lessons. Today was the first day of our bioinformatics workshop in Leuven, Belgium. We started out with some basic command line programming and eventually moved on to working with R Studio. What is this all about? It’s about getting some basic understanding of what your computer does and how your computer handles files. It’s about good data and bad data and losing the fear of the command line. We collected responses from the participants today about today’s take home messages. Continue reading
GPHN deletions in IGE and mutation-dependent recessive inheritance
Living in Cologne is a little tough at the moment. Currently, we are in the middle of the Cologne Carnival, the world’s oldest carnival, which started in 1829. Until the upcoming Wednesday the entire city is one big festival. In addition to the 1 million Cologne citizens probably another million tourists will join. Due to this (positive) distraction I will write less than usual. However, I still consider this week’s publications noteworthy. Continue reading
Program or be programmed – the EuroEPINOMICS bioinformatics workshop 2014
Join the genome hacking league. We are preparing a EuroEPINOMICS bioinformatics workshop in Leuven and I really, really encourage you to join us, as there are handful of place left. This will be the workshop that I always wanted to attend, but never got a chance to take part in. And yes, there is a final exam, but there is a chance that you might pass it. If you’re worried, skip ahead two paragraphs.
Mining GWAS mountains for missing heritability
What is missing? The catchy term “missing heritability” refers to a long-standing issue in human genetics that is particularly relevant to common diseases that are thought to have complex genetic architecture. Even though we know several thousands of risk factors for common diseases, the sum of all these risk factors only explains a small proportion of the genetic risk for disease. Where is all the remaining genetic disease risk hidden? A recent publication in PLOS Genetics suggests that known association peaks in genome-wide association studies (GWAS) may harbor more than one risk variant, turning GWAS peaks into mountain ranges. Also, this publication provides an interesting state-of-the art review on the role of common and rare variants with respect to missing heritability. Let’s turn back the clock and start with the decade-old debate on common versus rare variant models of human disease. Continue reading
Modifier genes in Dravet Syndrome: where to look and how to find them
Converging thoughts. During late 2013, I had several unrelated discussions about the possible role of genetic modifiers of SCN1A in Dravet Syndrome. To some extent, SCN1A is a paradox. One the one hand, the connection between Dravet Syndrome and SCN1A is one of the clearest connections between gene and disease that we see in genetic epilepsies. On the other hand, we see a remarkable phenotypic heterogeneity in families, and some presumably pathogenic SCN1A variants can also be identified in unaffected control individuals. This leaves us with the question whether there are genetic modifiers in Dravet Syndrome that might help provide some insight into additional mechanisms of disease. This post is a collection of 10 individual thoughts that emerged during the discussions last year. Continue reading
