Abstract
OBJECTIVE: To describe a dementia case clinically diagnosed as Alzheimer disease with a PRNP genotype usually associated with familial fatal insomnia. METHODS: Polymerase chain reaction amplification and subsequent direct sequencing of PGRN, MAPT, PSEN1, PSEN2, APP, and PRNP genes. RESULTS: A point mutation (D178N) was found in the PRNP gene. CONCLUSIONS: The mutation D178N in the PRNP gene associated with the M129 genotype is usually associated with familial fatal insomnia. However, a few cases have been reported with different clinical phenotypes. Here, we describe one of these cases and stress the importance of genetic screening of PRNP in early onset dementia cases.