A New Hope for Prion Disease Diagnosis
By Alexis Stefano, Behavioral Neuroscience, 2017
When depression sets in, or a sudden personality change occurs, it’s unlikely to be attributed to the onset of a deadly prion disease. While rare, these symptoms may point to something more complex and horrifying: Creutzfeldt- Jakob disease (CJD). Psychosis, memory failure, and blindness followed by a coma are all results of this disease.
Prions are contagious proteins that can cause normal proteins in the brain to fold incorrectly during synthesis. These clumpy, malformed products entangle with neurons and cause cell death, giving the patient’s brain a “sponge,” or “swiss cheese” appearance. Until recently, the only diagnostic tools available for diagnosing prion diseases were highly invasive procedures like lumbar punctures.
In old studies, the spinal fluid was analyzed for the presence of these troublesome protein clumps. However, these invasive procedures tend to miss 10–20% of all cases. Additionally, since doctors are hesitant to subject patients to these tests, the disease may go undiagnosed. As a result, medical professionals who are exposed to the patient’s brain tissue and spinal fluid are at increased risk of infection. There is no cure or treatment for CJD, but early diagnosis is essential for protecting caregivers.
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MRI and EEG from probable CJD patient[/caption]
Fortunately, researchers at the National Institute of Allergy and Infectious Diseases have developed a new non-invasive diagnostic tool to help diagnose CJD. The new procedure measures the levels of malformed proteins via a nasal swab. A fiber optic scope is placed into the patient’s nose and up into the nasal cavity where the olfactory bulbs are. So far, the test has worked well and has the potential to be much more accurate at diagnosing the disease than a lumbar puncture. In preliminary studies, the test identified 97% of positive cases without any false negatives. This is because the malformed proteins begin accumulating in the brain and take much longer to enter into the cerebral spinal fluid.
Although it can be argued that a fiber optic scope can make for an uncomfortable procedure, the new approach may enable easier diagnosis of prion diseases. Perhaps even non-prion protein aggregates in other neurodegenerative diseases, like Alzheimer’s, can be more easily diagnosed in the future.