Genetics

MS susceptibility genetics is mapped; outcome genetics is not. Three 2026 papers test inherited variation against what follows diagnosis. Abbadessa and colleagues genotype 291 brain donors and find the clinically worst genomic cluster carries the fewest chronic active rim lesions, while HLA genetic burden tracks the HLA-D stain used to score those lesions. Zimianiti and colleagues test the MS severity allele rs10191329 in 399,031 UK Biobank participants and see its clearest cognitive effect in people without MS. Kowalec and colleagues show a polygenic score for lymphocyte count predicts dimethyl fumarate lymphopenia beyond pre-treatment counts.