SNCA and Alzheimer disease: Abundance of α-synuclein (ALS versus PD cortex fc = 0.25, unadjusted p = 0.130; spinal cord fc = -0.28, unadjusted p = 0.500) and tau (ALS versus AD cortex fc = 0.12, unadjusted p = 0.593; spinal cord fc = 0.01, unadjusted p = 0.962) were similar between conditions in the detergent-soluble fraction of both spinal cord and cortex (Fig. 1B - C).