MTHFR and dementia: Recently, genetic polymorphisms in genes that have been implicated in AD, a primary neurodegenerative disease and the most common cause of dementia worldwide [85], include, among others, ABCA7 [86], PICALM [87], CLU [88], SLC24A4/RIN3 [89], ECHDC3 [90], MTHFR [91], as well as in insulin signaling such as INSR [92].