As mentioned earlier, Román [11] found a very high frequency (above 90%) of MTHFR gene mutations in an elderly population attending a memory clinic in the USA, with diagnoses ranging from mild cognitive impairment (MCI) to LOAD; about 65% had single mutations; the MTHFR-C667T mutation was found in 58.5% of the patients and 41.5% had the MTHFR-A1298C mutation whereas 20% were compound heterozygous for both mutations [11]. This evidence concerns the gene MTHFR and Cognitive impairment.