Plasma S1P d16.1 levels were significantly (p < 0.0001) lower in the DLB group (N = 28) versus the control group (N = 15) (Fig 1B) and significantly (p < 0.0001) lower in the AD group (N = 13) versus the control group (N = 15) (Fig 1B). This evidence concerns the gene MBTPS1 and Alzheimer disease.