An unusual familial dementia associated with G131V PRNP mutation.

To the best of our knowledge, this is the third report of a G131V mutation in the PRNP gene in the literature. Although ataxia and extrapyramidal findings accompanied dementia in patients reported in the previous literature, the members of the family in the present case primarily reported cognitive impairment, underscoring the importance of genetic evaluation in familial early-onset dementia patients, regardless of clinical and imaging features suggestive of alternative pathologies.