GFAP and Ataxia: GFAP‐Cre; hPDGFRAfl/+ KI mice, but not hPDGFRAfl/+ control mice, exhibited ataxia and tremors and were euthanized by P21 (Figure 8a, control, mean survival undefined, n = 13, KI, 19 ± 0.2745 days, n = 13, p = .0001, log‐rank (Mantel–Cox) test).