Wiring the Brain

Genome-wide association studies ( GWAS ) have been highly successful at linking genetic variation in hundreds of genes to an ever-growing number of traits or diseases. The fact that the genes implicated fit with the known biology for many of these traits or disorders strongly suggests (effectively proves, really) that the findings from GWAS are “real” – they reflect some real biological involvement of those genes in those diseases. (For example, GWAS have implicated skeletal genes in height, immune genes in immune disorders, and neurodevelopmental genes in schizophrenia). But figuring out the nature of that involvement and the underlying biological mechanisms is much more challenging. In particular, it is not at all straightforward to understand how statistical measures derived at the level of populations relate to effects in individuals. Here, I explore some of the diverse mechanisms in individuals that may underlie GWAS signals. GWAS take an epidemiolo...

“One day it's C-sections, the next it's pollution, now so many genes. Connect the dots, causation changes like the wind” That quote is from a brief conversation I had on Twitter recently, with someone who is sceptical of the evidence that the causes of autism are overwhelmingly genetic (as described here ). For me, it sums up a huge problem in how science is reported and perceived by the general public. This problem is especially stark when it comes to reportage of epidemiology studies, which seem to attract disproportionate levels of press interest. The problem was highlighted by reports of a recent study that claims to show a statistical link between delivery by Caesarean section and risk of autism. This study was reported in several Irish newspapers, with alarming headlines like “ C-sections ‘raise autism risk ’” and in the UK Daily Mail, whose headline read (confusingly): “ Autism '23% more likely in babies born by C-section': Women warned not to be alarmed by f...