BDNF and Cognitive impairment: Although amplicons within promotor BDNF_I did not show different methylation between investigated groups, most of the individual CpG loci that showed significantly different DNA methylation between individuals with dementia and MCI were in the BDNF_I2 amplicon of BDNF promoter I. Previous studies have also linked methylation alternations in BDNF promoters I and IV with cognitive deficits related to visuospatial abilities, memory [37], and neuropsychiatric symptoms of AD [11,12,38].