Scientists at the National Institutes of Health (NIH) are working to develop a rapid, practical test for the early diagnosis of prion diseases, and have recently modified their assay to offer the possibility of improving early diagnosis of Parkinson’s disease and dementia with Lewy bodies.
Led by researchers at the National Institute of Allergy and Infectious Diseases (NIAID), the NIH group tested 60 samples of cerebral spinal fluid, including 12 from people with Parkinson’s disease, 17 from people with dementia with Lewy bodies, and 31 controls, including 16 who had Alzheimer’s disease. The test correctly excluded all 31 controls, and diagnosed both Parkinson’s disease and dementia with Lewy bodies with 93% accuracy.
Test results were available within 2 days, a significant improvement over the performance of related assays that require up to 13 days. The group conducted the tests using real-time quaking-induced conversion (RT-QuIC), an assay developed and refined over the past decade at NIAID’s Rocky Mountain Laboratories. Scientists from Case Western Reserve University School of Medicine; Indiana University School of Medicine; University of California, San Diego; and the University of Verona collaborated on the project.
Multiple neurological disorders, including Parkinson’s disease and dementia with Lewy bodies, involve the abnormal clumping of a protein called alpha-synuclein into brain deposits called Lewy bodies. The pathological processes of these diseases resemble prion diseases in mammal brains. Like prion diseases, Parkinson’s disease and dementia with Lewy bodies result in progressive deterioration of brain function and, ultimately, death. Parkinson’s disease is about 1,000 times more common than prion diseases, affecting up to 1 million people in the United States, with 60,000 new cases diagnosed each year. Lewy body dementia affects an estimated 1.4 million people in the United States, according to the Lewy Body Dementia Association.
Early and accurate diagnoses of these brain disorders are essential for developing treatments and identifying patients eligible for clinical trials. The diseases typically progress for years before symptoms appear; once they do, distinguishing one disease from another can be difficult.
The NIAID group continues to adapt the RT-QuIC assay to detect additional types of neurological diseases with greater accuracy using the least-invasive patient sample possible—whether that is blood, nasal brushings, skin, or other samples. The group has also trained many international colleagues to use and advance the test.
- Groveman BR, Orrù CD, Hughson AG, et al. Rapid and ultrasensitive quantitation of disease-associated ?-synuclein seeds in brain and cerebrospinal fluid by ?Syn RT-QuIC. Acta Neuropathol Commun. 2018;6(1):7; doi: 1186/s40478-018-0508-2.