Nonetheless, the amyloid hypothesis is believed to hold due to APP mutations causing familial AD accounts for 5 to 10% of total AD, although the involvement of tau mutations has not yet been observed in familial AD, in contrast to other tauopathies, such as frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). This evidence concerns the gene MAPT and amyloidosis.