CBS and red-green color blindness: CSF Ab42 levels resulted lower in CBS [patients number (n) = 42 and 26] when compared with healthy controls (n = 92 and 108 respectively) (p < 0.001) [24, 25]; although in one study, Ab42 levels of 32 CBS patients resulted within normal range, due to a significant representation of CBD (n = 26) rather than CBS-AD (n = 4) patients [26].