apo e4

Introduction

Allelic form of apo E

Structure

• Arg :site R112
• Met :site M125
• Arg :site R158

Pathology

• associated with 50% of familial late-onset Alzheimer's disease (AD)
  • each apo-E4 allele confers a 3-4-fold increased risk of AD
    • 2-fold risk of AD among women
    • only slight increase in risk of AD among men
  • most patients with AD do not carry the apo E4 allele
    • 48% overall, 61% in Northern Europe
• cortical thickness of the left entorhinal cortex is lowest in children with the apoE4 allele < apoE3 < apoE2
• apo E4 may also be a risk factor for amyloid angiopathy, independent of AD
• the apo E4 allele is associated with a significantly higher amyloid plaque burden than observed with the apo E3 & apo E2 alleles
• the higher amyloid plaque burden & risk of AD may related to differential binding of apo E4 to the A4 amyloid peptide or differential processing of A4-bound apo E4
• thus apo E4 appears to enhance A4 deposition in the brain, especially A4/40 by diminishing A4 clearance.
• the burden of neurofibrillary tangles is allegedly not as sensitive to the apo E4 allele as the burden of amyloid plaques
• apo E4 may also carry a 4-fold higher risk of cardiovascular disease
• cognitive impairment in patients with early Parkinson's disease & the apoE4 allele may be mitigated by exercise

Laboratory

• apolipoprotein E4 in blood

More general terms

• apolipoprotein E (APOE)

Additional terms

• Alzheimer's disease (AD)
• apolipoprotein E genotype
• apolipoprotein-E gene
• cerebral amyloid angiopathy (CAA)