The MAPT N279K mutation was discovered in the white pallidopontonigral degeneration (PPND) kindred20 and was also found in 6 Japanese kindreds.21, 22, 23 In the present work, we further identified two novel Japanese families with hereditary tauopathy caused by the N279K mutation, and we investigated the abundance and extent of tau deposits in patients harboring the MAPT N279K mutation derived from three pedigrees, including these two families. The gene discussed is MAPT; the disease is frontotemporal dementia.