PSAP and frontotemporal dementia: Third, NCL is characterized by pathological alterations typical of FTD and vice versa: NCL presents a different degree of TDP-43 phosphorylation and GRN-associated FTD is characterized by the elevation of lysosomal proteins and accumulation of saposin B, subunit c of mitochondrial ATP synthase (SCMAS), ubiquitin and p62 protein48.