region were regressed from these transcriptomes. Normalized gene expression values derived from alignment to GRCh38 were assigned the lift-over to GRCh37 gene coordinates for purposes of defining 1MB cis-variant windows used to acquire variants passing quality control and filtered for those sites within the LD reference panel. This GRCh37 genome build matched variants to gene locus expression for all gene features and was used to estimate mRNA weights. After quality control, 13,650 mRNAs remained and were considered for the TWAS. Genome-wide genotypes were generated as previously described22,58,59, and quality control of the genotypes was the same as was done for the discovery dataset. Among the 783 subjects included in the analysis, 480 were female and mean age at death was 88 years old.
