LAUSR

To the Editor, Genetic transmissible spongiform encephalopathy (TSE) diseases are always associated with one of the more than 50 disease-associated point or insert mutations of the PrP gene (PRNP) [12] and represent approximately 10 to 20% of all forms of TSE diseases [9]. Each mutation is often associated with specific clinic-pathological phenotype [12] that are generally represented by Creutzfeldt-Jakob disease (CJD) [3, 8], Gerstmann–Sträussler–Scheinker disease or inherited prion protein cerebral amyloidoses [5], and fatal familial insomnia [4]. The methionine/valine polymorphism at codon 129 of PRNP plays also a role in determining the disease phenotype, especially when co-segregates with the pathogenic mutation [3]. Most PRNP mutations responsible for the CJD phenotype, including the R208H, are extremely rare and often there is no evidence of CJD in other family members. In particular, the R208H mutation co-segregates either with methionine or valine at codon 129 and it has been fully described in only 12 patients carrying M129 and 4 patients with V129 [8]. Here, we report clinical and neuropathological details of the fourth worldwide case of CJD carrying the rare R208H-129 Val PRNP genotype with a suggestive positive family history for dementia.