Classification of sporadic CJD subtypes in the Dutch population based on combined molecular and histopathological assessment.

Nomenclature is largely based on the codon 129 genotype, which can be either methionine (M) or valine (V) and the PrPSc type (type 1 or 2, according to Parchi et al.) Since both MM2 and MV2 groups are associated to 2 distinct phenotypes, these are further defined with a third parameter (capital letter) referring to distinctive histopathological features: K kuru type amyloid plaques, C predominant cortical pathology with confluent vacuoles and perivacuolar PrP staining, T prominent thalamic pathology with atrophy.*In 13 patients, neuropathological examination identified the distinctive feature of the MM/MV 2C subtype (i.e. grape-like clusters of spongiform change with a coarse PrP immunohistochemical staining pattern), but the type 2 band on immunoblotting was not detected.