We assessed the relationship between the AD-PD pleiotropic locus on chromosome 17 and MAPT transcript levels within the brain (target id = GI_8400714-A and reference sequence = NM_016841. 1 in GSE15222, for additional details see references 16 and 32). Since rs393152 was not available in the GEO dataset, we focused on rs422112 within the CRHR1 locus on chromosome 17, the best available proxy (closest distance and r2 > 0.98) for rs393152. We used an additive model with minor allele (T) counts coded as 0, 1, and 2. Given the allele frequencies and near complete LD between rs393152 and rs422112, the ‘A’ allele of rs393152 tags the ‘C’ allele of rs422112 and the ‘G’ allele of rs393152 tags the ‘T’ allele of rs422112. Using linear regression, co-varying for the effects of age at death, APOE ε4 carrier status, diagnosis (AD cases vs. controls), brain tissue region (frontal, parietal, temporal, or cerebellar), postmortem interval, institute source of sample, and hybridization date, we evaluated the relationship between rs422112 and MAPT transcript expression levels. Across all cases and controls, we found a strong association
