MAPT and Alzheimer disease: However, previous neuroimaging [34, 51] and neuropathological studies [40] suggest a multifactorial aetiology of WMH, in addition to SVD it may also include degenerative axonal loss secondary to the deposition of cortical AD pathology, i.e. hyperphosphorylated tau (HPτ) and amyloid-beta (Aβ).