14,3,3 protein in CJD

Castellani et al. (Case Western Reserve, Italy) studied 90 patients with CJD. IN addition to neurologic deterioration and spongiform deterioration of the brain in sCJD, there is accumulation of proteinase K resistant prion protein (PrP-sc). Most cases are sporadic without prion protein gene (PRNP) or exposure to exogenous prions. The authors classify sCJD based on electropheretic motility of K resistant PrP-sc. Type I sporadic CJD patients are homozygous methionine at codon 129 (sCJDMM1) with phenotype of advanced age, rapid dementia and periodic sharp waves on EEG. sCJDMV1 also has classic phenotype and the two classic forms together account for 70 % of sporadic CJD. The alternate types have a younger age at onset (CJDVV1) ataxia at presentation (sCJDMV2 and sCJDVV2),a slower course and a lack of periodic sharp waves on EEG. The study looked at the sensitivity of 14,3,3 for the different types of sCJD and found an overall sensitivity of 87 %, with 94 % sensitive in classic forms and 57-84 % in nonclassic forms of CJD. Nonclassic presentations are harder to diagnose as they have such symptoms as vertigo, hemianopsia, gait difficulty, and hallucinations. Other tests for CJD include NSE (neuron specific enolase and atu tau protein in CSF). Periodic sharp waves are only present half the time and only the in the midstages of the disease. Nomenclature for the nonclassic forms has included the Heidenham variant (visual symptoms predominate) and Brownell-Oppenheimer variant (cerebellar ataxis is presenting sign). Two other studies in the same issue looked at MRI in sCJD. Shiga et al. looked at 24 cases of 26 that had abnormalities on diffusion weighted imaging (DWI) 3 in striatum,esp caudate, 10 linear lesions in cortex, and 11 in both. 12.5 percent of controls were false positives. In yet another study in same issue, Meissner et al. found that MRI basal ganglia hyperintensity on T2 images are seen in most MV2 cases (variants that may have normal 14,3,3 testing). There was no correlation with basal ganglia abnormality on MRI and eps symptoms. Most patients, whether atypical or not, will have abnormalities on MRI or 14,3,3, testing or both.