A deletion in the repeat 2 region (R2) of the PRNP gene associated with a phenotype of cerebellar-pyramidal syndrome suggestive of Gerstmann-Straussler ataxia (with videotape)

We report a case of a patient affected with a cerebellar-pyramidal syndrome and a progressive disease course with apparently negative family history. The onset was 40 years with Stereotypie movements, cerebellar symptoms and personality changes. We found the patient's DNA negative for mutations causing movement disorders such as Huntington's disease and dominant ataxias. Molecular analysis included a search for mutation in the PrP gene (PRNP) because the illness was suggestive of the Oerstmann-Straussler syndrome (GSS). After sequencing the open reading frame (ORF) of the PRNP, we found a deletion in the R2 element of the octarepeat region and valine homozygosity at codon 129. Different deletions within the ORF PRNP may occur in the general population resulting as a genetic polymorphism. The R2 octarepeat deletion has been described in an individual affected by sporadic Creutzfeldt-Jakob disease (CJD) and in five healthy controls associated with methionine at codon 129. We suggest that association between R2 octarepeat deletion and val/val hemozygosity at codon 129 may predispose to a neurological disease with cerebellar phenotype similar to GSS.