GRN and Apathy: Similar to C9orf72, GRN carriers had apathy as the predominant symptom (mean severity score at 1-4 years: 1.34 [95% CI, 1.19-1.49] points), which increased into intermediate-late stages (mean severity score at 4-8 years: 1.69 [95% CI, 1.37-2.01] points; at 8-12 years: 1.93 [95% CI, 1.57-2.29] points).