Several factors are considered as AD markers in the cerebrospinal fluid (CSF), including concentration and ratio of Aβ42 to Aβ43 and Aβ40 to Aβ42 peptides, amount of tau protein and the level of its phosphorylation, concentration of apolipoprotein E (ApoE), and probably concentration of dimethylarginines and homocysteine [2, 18]. The gene discussed is MAPT; the disease is Alzheimer disease.