Dura mater graft-associated Creutzfeldt-Jakob disease in Japan: clinicopathological and molecular characterization of the two distinct subtypes.

Up to February 2008, a total of 132 patients with dura mater graft-associated Creutzfeldt-Jakob disease (dCJD) have been identified in Japan, accounting for a majority of the world's patients with dCJD. The patients received dura mater grafts from 1978 to 1993. Lyodura (B. Braun, Melsungen, Germany) was used for all the patients in whom the brand name of the dura mater could be identified. After the incubation period of 1 to 25 years (mean, 11.8 years), CJD appeared from 1985 through to 2006. We analyzed clinical, pathological, and molecular features in 74 patients with dCJD who had been prospectively registered by the CJD Surveillance Committee. The cases of dCJD could be classified into two distinct clinicopathological phenotypes: a non-plaque type, showing typical features identical with those of classic CJD, and a plaque type, characterized by atypical features, including slow progression, lack of or late occurrence of periodic sharp wave complexes on EEG, and plaque formation in the brain. The plaque type accounted for one-third of the pathologically confirmed or clinically diagnosed cases of dCJD. The non-plaque type was associated with methionine homozygosity at codon 129 (129M/M) of the PrP gene in all patients, except for in one patient with the 129M/valine (V) genotype and type 1 protease-resistant PrP (PrP(res)), whereas the plaque type was always associated with the 129M/M genotype and the intermediate type between types 1 and 2 of PrP(res) in all cases. Thus, the clinicopathological and molecular features of the plaque type are distinct from those of the non-plaque type, suggesting contamination of the dura mater grafts with different prion strains.