Newly Discovered Type of Dementia May Account for 20 Percent of Cases

A new study from the University of Kentucky in JAMA Neurology has classified a novel form of dementia characterized by the toxic accrual of four different proteins in the brain, and suggests that many people diagnosed with Alzheimer's disease may be suffering from this disorder, reports New Atlas . Last year a landmark study described a type of dementia founded on the abnormal accumulation of a protein called TDP-43, termed limbic-predominant age-related TDP-43 encephalopathy (LATE). The authors suggested about 20 percent of Alzheimer's cases may actually be misdiagnosed LATE cases. The latest investigation analyzed brain autopsy data from 375 subjects, who were closely monitored for more than a decade before their death. The researchers examined accumulations of not only amyloid-beta, tau, and TDP-43, but also alpha synuclein, a protein that builds into Lewy bodies. About 20 percent of all subjects with dementia at the time of death showed indications of accumulating all four kinds of toxic proteins, and those with all four of these pathologies exhibited the most severe dementia symptoms. Individuals with so-called quadruple misfolded proteins pathologies progressed from mild cognitive impairment to dementia faster than those with three or fewer pathologies. The autopsy findings suggest amyloid-beta aggregations may precede abnormal accumulations of the other three proteins — and Kentucky's Eric Abner said this research complicates Alzheimer's research by implying that treatments focusing on one pathology may overlook the other processes that seem to be contributing.