A patient with dementia with Lewy bodies and codon 232 mutation of PRNP

The authors describe a patient who had a point mutation at codon 232 of the prion protein gene, resulting in the substitution of methionine for arginine (M232R). The patient developed dementia and died 6 years after its onset. Autopsy revealed dementia with Lewy bodies, not Creutzfeldt–Jakob disease. Although the M232R mutation has been reported to cause Creutzfeldt–Jakob disease, findings in our patient suggest that not all patients presenting progressive dementia with M232R mutation have Creutzfeldt–Jakob disease.