MTA2 and red-green color blindness: Reactive astrocytes (using GFAP as marker; Figure 2A–D) were increased compared to controls in PiD and GGT cases, significant in the latter (Figure 2I; Mann–Whitney; mean: Control = 2.00, GGT = 4.822; p = 0.0317); in contrast, there was no difference in reactive astrocyte signal between CBD cases and controls (Figure 2I).