Familial Alzheimer-like prion disease

Familial Alzheimer-like prion disease (Orphanet code 280397) is an extremely rare inherited prion disease (transmissible spongiform encephalopathy) caused by mutations in the PRNP gene, which encodes the prion protein. Unlike typical Alzheimer disease, this condition is classified among prion diseases, but it presents with clinical and neuropathological features that closely mimic Alzheimer disease, including progressive dementia, memory loss, and cognitive decline. The brain is the primary organ affected, with neurodegeneration characterized by spongiform changes, neuronal loss, and the accumulation of abnormal prion protein. Notably, affected individuals may also show amyloid plaques and neurofibrillary tangles reminiscent of Alzheimer disease, which can complicate the clinical and pathological distinction between the two conditions. The disease follows an autosomal dominant inheritance pattern, meaning that a single copy of the mutated PRNP gene inherited from an affected parent is sufficient to cause the condition. Onset typically occurs in adulthood, and the disease is progressive, leading to severe cognitive impairment, behavioral changes, and eventually death. Additional neurological features may include myoclonus, ataxia, and psychiatric symptoms such as depression or personality changes. Diagnosis is supported by genetic testing for PRNP mutations, neuroimaging, and cerebrospinal fluid biomarkers, though definitive diagnosis may require neuropathological examination. There is currently no cure or disease-modifying treatment for familial Alzheimer-like prion disease. Management is supportive and symptomatic, focusing on maintaining quality of life, managing behavioral and psychiatric symptoms, and providing palliative care as the disease progresses. Genetic counseling is recommended for affected families to discuss the implications of autosomal dominant inheritance and the availability of predictive genetic testing for at-risk relatives.

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