A new sporadic prion protein disease has been discovered. Variably protease-sensitive prionopathy (VPSPr), as it has been named, is the second type of complete sporadic disease to be identified since Creutzfeldt-Jakob disease (CJD) was reported in the 1920s. The landmark finding from the National Prion Disease Pathology Surveillance Center at Case Western Reserve University is published in the August issue of Annals of Neurology.
Normally, the human prion protein gene comes in three types due to its capability to encode prion proteins that contain only the amino acid methionine, commonly identified as M, both methionine and valine, commonly identified as V, or only for the amino acid valine at position 129. Therefore, when it comes to the prion protein gene unaffected people can be identified as 129MM, 129MV or 129VV. Sporadic CJD (sCJD), which is the most common human prion disease, can affect patients who have any one of the three types of the prion protein gene. In 2008, Pierluigi Gambetti, MD, and Wen-Quan Zou, MD, PhD, with collaborators, reported the discovery of this novel disease, which affected patients who exhibit only one of the three types of the prion protein gene. In this follow-up study, they discovered that all three genetic groups can be affected also by this novel disease which now joins sCJD in displaying this feature. However, VPSPr is associated with an abnormal prion protein that exhibits characteristics very different from those of sCJD, as well as other prion diseases, suggesting that it may be caused by a different mechanism, perhaps more akin to other neurodegenerative diseases, such as Alzheimer's disease. This finding may exemplify, for the first time, the possibility that the prion protein affects the brain with different mechanisms.
While examining cases received at the National Prion Disease Pathology Surveillance Center where he is the director, Dr. Gambetti observed that a subset of cases had clinical
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Case Western Reserve University