BACE1 and Alzheimer disease: Finally, when methylation values for all CpGs analysed (region −904 to +295) were combined, global hypomethylation at the bace-1 promoter became evident in Tg animals compared to their WT littermates in the cortex (Fig. 2H), but not in the hippocampus (Fig. 2I), an aspect likely to be related to the regional progression of the AD pathology and suggesting that most significant impact on DNA hypomethylation might occur at the earlier stages of intracellular Aβ pathology.