GRN and Huntington disease: From the 98 articles, 44 papers were removed because of their focus on CSF biomarkers and amyloid PET, 29 papers were removed because of their focus on only AD, five papers were removed because of their focus on progranulin mutations rather than the diagnostic ability of FDG-PET, two papers focused on amyotrophic lateral sclerosis, seven papers used tau PET, three focused on corticobasal syndrome, and one paper was removed because of its focus on Huntington’s Disease.