C9orf72 and frontotemporal dementia: Notable distinctions such as dipeptide repeats (DPR) pathology [42, 43] and increased tau co-pathology in C9orf72 [44], lipofuscin presence in the retina of GRN carriers [45], and the heterogeneity of tau inclusion morphologies in MAPT versus sporadic tauopathies [46], as well as variations in biomarkers, including white matter hyperintensities in GRN FTD [47, 48] and altered CSF biomarker values in familial versus sporadic FTD [49], underscore the complexity and heterogeneity inherent in FTD.