Figure 3.

Genetic risk factors. Polymorphisms in regulatory regions (A) as well as Tau gene duplication (C) may account for an increased tau expression. This is considered a disease risk factor because of the possible tendency of tau molecules in excess to aggregate into oligomers and fibrils. Some apparently benign tau polymorphisms (B) can produce an overt tau pathology only in association with mutations present in other genes relevant to neurodegenerative diseases (C9ORF72 is an example).