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

The genetics of treatment response in newly diagnosed epilepsy

Two questions. There are two main questions that we would like to answer with genetics in the field of epilepsy. First, are there genetic risk factors for epilepsies and if so, what are they? Secondly, are there genetic factors that help us understand how patients react to treatment, i.e. are there genes that predispose to response to antiepileptic drugs or that might be associated with side effects? While we have made much progress in answering the first question by identifying many epilepsy genes, there have been few answers for the second question, the field of pharmacogenomics. Now, a recent study in Human Molecular Genetics looks at potential genetic risk factors for the response to antiepileptic drugs in newly treated epilepsy. This is a study that needed to be performed and that we were waiting for. Continue reading