GPX3 and amyotrophic lateral sclerosis: Four genes (of six) discovered in blood were further replicated in brain eQTL SMR analysis at the nominal threshold (Bonferroni-corrected p-value < 0.0083), indicating that these genes (GPX3, C9orf72, SCFD1, RP11-529H20.6) are also likely to contribute to ALS risk in the brain (Additional file 1: Table S14).