A new study that involves 19 researchers from several institutions, has suggested a new way to classify patients with Alzheimer’s disease. The study suggests that Alzheimer’s, like breast cancer, is not one disease. We should think of the disease as six distinctly different conditions instead of one single disease.
Scientists tested 4,050 people with late-onset Alzheimer’s disease into six groups based on their cognitive functioning at the time of diagnosis and then used genetic data to find biological differences across these groups.
The participants received cognitive scores in four domains: memory, executive functioning, language, and visuospatial functioning.
The largest group (39%) had scored in all four domains that were fairly close to each other. The next largest group (27%) had memory scores substantially lower than their other scores. Smaller groups had language scores substantially lower than their other scores (13%), visuospatial functioning scores substantially lower than their other scores (12%), and executive functioning scores substantially lower than their other scores (3%). There were 6% who had two domains that were substantially lower than their other scores.
The participants came from five studies, and it took more than two years to standardize the neuropsychological test scores across all the studies in order to detect meaningful patterns. The mean age was 80, 92 percent self-reported white race, and 61 percent were female.
For the study, scientists used genome-wide genetic data to find out if the subgroups are biologically distinct.
Specialists discovered 33 single nucleotide polymorphisms (SNPs) – specific areas all through the genome – where the hereditary affiliation was extremely solid for one of the subgroups. These genetic relationships were more grounded than the most grounded impacts found by a before and much larger international consortium study where Alzheimer’s disease was treated as a single homogeneous condition.
Quite a while back, the International Genomics of Alzheimer’s Project Consortium distributed the largest genome-wide association of Alzheimer’s infection and found around 20 SNPs related to Alzheimer’s disease risk.
This investigation discovered 33 extra SNPs with much more grounded associations with a solitary subgroup.
The investigation likewise found an especially strong connection between a specific variation of the APOE gene and risk for the memory subgroup. The APOE e4 allele is an extremely solid hazard factor for building up Alzheimer’s infection for individuals with European ancestry, and it additionally seems to impact which psychological subtype of Alzheimer’s person man is probably going to create.
Individuals can presently see whether they have an APOE e4 allele with direct-to-consumer testing; nonetheless, the scientists take note of that numerous individuals with an APOE e4 allele never build up Alzheimer’s disease and numerous who don’t carry any known genetic risk factor nevertheless end up with the condition.
However, scientists want to find a cure for Alzheimer’s by 2025, so far no one has been able to develop an effective treatment let alone a cure. But this study suggests that thinking of Alzheimer’s disease as six distinct conditions may provide a way forward.
Shubhabrata Mukherjee, research assistant professor in general internal medicine at the University of Washington School of Medicine said, “This study is not the end, it’s a start.”
The study is published in the recent issue of Molecular Psychiatry.