MAPT and red-green color blindness: MAPT mutations have been linked to a variety of neurodegenerative diseases with abnormal tau accumulation, and mainly to frontotemporal dementia (FTD) (Hutton et al., 1998) but also to other sporadic tauopathies, including progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and various disorders with more unusual tau pathology (Conrad et al., 1997; Höglinger et al., 2011; Momeni et al., 2009).