Whereas beta-amyloid triggers the formation of neurofibrillary tangles, it is the formation of neurofibrillary tangles rather than beta-amyloid itself that aggravates alzheimer’s symptoms. In fact, in the case of FTDP-17, which is a chromosome 17-type dementia involving mutations in the tau gene, the symptoms of dementia are manifested without any beta-amyloid aggregations.