Popper, Kuhn, and the paradigm shifts of the genomic revolution

Paradigm shifts no more. During our bioinformatics workshop in Leuven, Roland pointed out that I tend to use the phrase “paradigm shift” too liberally. In fact, the concept of paradigm changes in science was made popular by Thomas Kuhn, an American physicist, historian, and philosopher of science. Kuhn believed that scientists work within a given set of paradigms and believes that they don’t really question them – until everything falls apart. Let me take you on a brief journey through the philosophy of genomics starting with Kuhn’s nemesis, Karl Popper. 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

Transmission of rare variants in parent-offspring trios – power or no power?

My untested assumption. Recently, I have boasted quite a bit about the power of the trio design, i.e. the inclusion of patients and parents in the analysis of rare genetic variants. Rare variants, in contrast to monogenic variants that arise de novo, are usually transmitted from unaffected parents and are the big unknown of modern day genetic studies. Much of the missing heritability may be accounted for by rare variants, but identifying these variants from genomic noise is difficult. Power calculations for association studies usually suggest that thousands, if not tens of thousands, of patients are necessary to identify these variants with sufficient statistical certainty, a sample size that the field of epilepsy research may never arrive at. So what about switching to parent-offspring trios? Would this help us? Follow me on a brief statistical journey through the land of rare variants. Continue reading