Prion protein amyloidosis with divergent phenotype associated with two novel nonsense mutations in PRNP

• Published in: Acta neuropathologica Vol. 119; no. 2; pp. 189 - 197
• Main Authors: Jansen, Casper, Parchi, Piero, Capellari, Sabina, Vermeij, Ad J., Corrado, Patrizia, Baas, Frank, Strammiello, Rosaria, van Gool, Willem A., van Swieten, John C., Rozemuller, Annemieke J. M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-02-2010; Springer Nature B.V
• Subjects: Adult; Base Sequence; Blotting, Western; Brain - pathology; Cerebral Amyloid Angiopathy, Familial - genetics; Cerebral Amyloid Angiopathy, Familial - pathology; Codon, Nonsense; Female; Gerstmann-Straussler-Scheinker Disease - genetics; Gerstmann-Straussler-Scheinker Disease - pathology; Humans; Medicine; Medicine & Public Health; Middle Aged; Neurosciences; Original; Original Article; Pathology; Phenotype; Prion Proteins; Prions - genetics; PrPSc Proteins - genetics; Angiopathy; Prion; Amyloid; Gerstmann-Sträussler-Scheinker disease; Tau protein; Creutzfeldt-Jakob disease
• ISSN: 0001-6322; 1432-0533
• DOI: 10.1007/s00401-009-0609-x

Stop codon mutations in the gene encoding the prion protein (
PRNP
) are very rare and have thus far only been described in two patients with prion protein cerebral amyloid angiopathy (PrP-CAA). In this report, we describe the clinical, histopathological and pathological prion protein (PrP
Sc
) characteristics of two Dutch patients carrying novel adjacent stop codon mutations in the C-terminal part of
PRNP
, resulting in either case in hereditary prion protein amyloidoses, but with strikingly different clinicopathological phenotypes. The patient with the shortest disease duration (27 months) carried a Y226X mutation and showed PrP-CAA without any neurofibrillary lesions, whereas the patient with the longest disease duration (72 months) had a Q227X mutation and showed an unusual Gerstmann-Sträussler-Scheinker disease phenotype with numerous cerebral multicentric amyloid plaques and severe neurofibrillary lesions without PrP-CAA. Western blot analysis in the patient with the Q227X mutation demonstrated the presence of a 7 kDa unglycosylated PrP
Sc
fragment truncated at both the N- and C-terminal ends. Our observations expand the spectrum of clinicopathological phenotypes associated with
PRNP
mutations and show that a single tyrosine residue difference in the PrP C-terminus may significantly affect the site of amyloid deposition and the overall phenotypic expression of the prion disease. Furthermore, it confirms that the absence of the glycosylphosphatidylinositol anchor in PrP predisposes to amyloid plaque formation.