Prion disease may manifest as?
Ans. d (All of the above) (Ref. Nostric Warden Principles of Neurology, p. 224)PRIONS are Proteinaceous particles devoid of nucleic acid, that cause slowly evolving spongiform degeneration of central nervous system without production of immune response and due to abnormality of protein folding. Prion diseases are caused by the conversion of a normal (predominantly (3-helical) protein termed prion protein (PrPc) to a a-pleated form (PrPsc), which is transmissible. PrPsc resists protease degradation and facilitates the conversion of still more PrPc to PrPsc. Accumulation of PrPsc results in spongiform encephalopathy and dementia, ataxia, and death. It can be sporadic (Creutzfeldt- Jakob disease--rapidly progressive dementia), inherited (Gerstmann-Straussler-Scheinker syndrome), or acquired (kuru).New concepts have emerged from studies of prions:(1) Prions are the only known infectious pathogens that are devoid of nucleic acid; all other infectious agents possess genomes composed of either RNA or DNA that direct the synthesis of their progeny.(2) Prion diseases may be manifest as infectious, genetic, and sporadic disorders; no other group of illnesses with a single etiology presents with such a wide spectrum of clinical manifestations.(3) Prion diseases result from the accumulation of PrPSc, the conformation of which differs substantially from that of its precursor, PrPC.(4) PrPSc can exist in a variety of different conformations, each of which seems to specify a particular disease phenotype.Master's Criteria for GD (1979)* NeuropaBiologically confirmed spongiform encqdialopathy in a patient of progressive demantia with any one of the following:* Myoclonus (90% cases)* Extrapyramidal signs (80% cases)* Pyramidal signs (55% cases)* EEG (triphasic electrical Bursts)* Cerebellar signs (30% cases)
Sporadic
Inherited
Familial
All of the above
Infection