Giving Compass' Take:

• Researchers identified substantial biological differences among cognitively defined subgroups of Alzheimer's patients, which scientists think will help create a precision medicine approach to treat the disease. 

• How can philanthropists help fund more Alzheimer's research and studies such as this one? 

• Read about how the broader health system may be hindering progress finding a cure of Alzheimer's. 

"Alzheimer's, like breast cancer, is not one disease," said lead author Shubhabrata Mukherjee, research assistant professor in general internal medicine at the University of Washington School of Medicine. "I think a good drug might fail in a clinical trial because not all the subjects have the same kind of Alzheimer's.

This study, published in the recent issue of Molecular Psychiatry, involves 19 researchers from several institutions, including Boston University School of Medicine, the VA Puget Sound Health Care System and Indiana University School of Medicine.

The researchers put 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 implications are exciting," said corresponding author Paul Crane, professor of general internal medicine at the University of Washington School of Medicine. "We have found substantial biological differences among cognitively defined subgroups of Alzheimer's patients." Identification of cognitive subgroups related to genetic differences is an important step toward developing a precision medicine approach for Alzheimer's disease.

The study also found a particularly strong relationship between a particular variant of the APOE gene and risk for the memory subgroup. The APOE e4 allele is a very strong risk factor for developing Alzheimer's disease for people with European ancestry, and it also appears to influence which cognitive subtype of Alzheimer's a person is likely to develop.

While world leaders 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.

"This study is not the end, it's a start," said Mukherjee.

Read the full article about Alzheimer's research at ScienceDaily.