Genetics

This post covers Olsson, Barcellos and Alfredsson's 2017 Nature Reviews Neurology review on gene-environment interaction in multiple sclerosis. It centres on the review's table of 13 risk factors and the three rows where a modest exposure combines with HLA genotype to produce odds ratios around 14 to 15, examines which factors show no interaction and what the authors read into that, covers the adolescence timing window and the oral tobacco result that separates nicotine from smoke, gives the attributable fractions behind the prevention advice, and closes on the drop in sibling relative risk estimates and the uneven evidence grades in the table.