Neurologists are familiar with prion diseases. And so is the general public, not least because of the mad cow disease scare. The quintessential prion disease is Creutzfeldt Jakob disease (CJD), and this is readily identified by its rapidly progressive course, and by typical blood, brain imaging, cerebrospinal fluid (CSF), and brain pathology features.
There has however been a lot of whispering speculation that some other neurological disorders are really prion diseases camouflaging as neurodegenerative conditions. Most of the speculation is around Parkinson’s disease (PD), with headlines such as, Is Parkinson’s Disease a Prion Disorder? and The prion hypothesis of Parkinson’s disease.
Pushing the ‘prion-like’ hypothesis comes a paper straight off the press asserting that multiple system atrophy (MSA) is likely to be a prion disease.Published in Proceedings of the National Academy of Sciences, the study demonstrates that human brain homogenates from MSA patients transmit α-synuclein, and produce neurological disease in susceptible mice. More importantly, specimens from Parkinson’s disease (PD) patients and normal controls did not transmit this activity.
MSA, along with other disorders such as progressive supranuclear palsy (PSP) and Lewy body disease (LBD) are really cousins of Parkinson’s disease (PD). It is interesting therefore that this transmissibility is only seen with MSA, and not even in PD. The findings however seem authentic enough, even if slightly still speculative. The paper however comes from one of the gurus of prion diseases, Stanley Prusiner. There must therefore be something about this prion hypothesis, and the next few papers will surely convert this into established theory. Or perhaps not, I hear you whisper.