Early onset Alzheimer dementia

  • Early onset Alzheimer disease is defined as age of onset younger than 65 years of age (Mendez 2019)
  • Early onset Alzheimer disease (EOAD) makes up 5-6% of AD cases and is the most common cause of early onset neurodegenerative dementia (Mendez 2019)
  • 1/3 EOAD cases present with predominant language, visuospatial, or other phenotype compared to typical AD presentation (amnestic type) (Mendez 2019)
  • Amyloid PET is positive in most EOAD, it is more helpful to confirm diagnosis in EOAD than LOAD because most patients in EOAD age range are not expected to have age-associated brain amyloid deposition (Mendez 2019)
  • Most EOAD have sporadic, nonfamilial form (or have unidentified polygenic mutations). (Mendez 2019)
    • Only 11% have association with one of 3 known autosomal dominant mutations:
      • APP
      • PSEN1
      • PSEN2


References

Mendez, M. F. Early-onset Alzheimer Disease and Its Variants: Contin. Lifelong Learn. Neurol. 25, 34–51 (2019). https://pubmed.ncbi.nlm.nih.gov/30707186/