Investigators at the Florida campus of Mayo Clinic identified distinct subtypes of Alzheimer’s disease, including one that occurs most often in middle-aged adults and is rapidly progressive and another type that occurs most often in very old patients that advances slowly. In the study, published in the July 28 online edition of Lancet Neurology, the neuroscientists say that patients in the first subtype are more often misdiagnosed during life and thought to have disorders that are unrelated to Alzheimer’s disease, such as frontal lobe dementia or progressive aphasia.
According to the lead investigator, Melissa Murray, Ph.D., a research fellow, there may be differences in the gene for tau protein (which makes up “tau tangles”) that predisposes individuals to the rapidly progressing form of Alzheimer’s disease. In contrast, risk for Alzheimer’s disease that is slowly progressive and common in very old patients may be linked to differences in the gene for apolipoprotein E.
“As effective disease-modifying therapies are developed to treat Alzheimer’s disease, it will be important to recognize early onset, rapidly progressive variants of this disorder so that these patients may benefit from proper therapy,” says the study’s senior investigator, neuropathologist Dennis Dickson, M.D. “A goal of ongoing research efforts at Mayo Clinic is to identify better ways to diagnosis subtypes of Alzheimer’s disease in life with genetic tests, medical imaging and blood or spinal fluid tests.”