Apolipoprotein E polymorphism in patients with different neurodegenerative disorders

Area of Science:

• Neuroscience
• Genetics
• Neurology

Background:

• Apolipoprotein E (ApoE) is implicated in Alzheimer's disease (AD) pathology, including neurofibrillary tangles and beta-amyloid plaques.
• Three common ApoE alleles exist: epsilon 2, epsilon 3, and epsilon 4, with epsilon 4 being a known risk factor for AD.

Purpose of the Study:

• To investigate the frequency of ApoE genotypes and alleles in Finnish patients with various neurodegenerative disorders.
• To determine if the ApoE epsilon 4 allele is associated with conditions beyond AD.

Main Methods:

• Genotyping of Apolipoprotein E (ApoE) was performed on 188 patients with neurodegenerative disorders (AD, VAD, PD, PDD, LB, FD, DS) and 60 controls.
• ApoE polymerase chain reaction products were analyzed using the restriction enzyme Hha I to determine genotypes and allele frequencies.

Main Results:

• The ApoE epsilon 4 allele frequency was significantly higher in Alzheimer's disease (AD) patients (0.44) compared to controls (0.17).
• Elevated ApoE epsilon 4 frequencies were also observed in Vascular Dementia (VAD, 0.35), PD with dementia (PDD, 0.38), Lewy body variant of AD (LB, 0.28), and Frontal Dementia (FD, 0.39).
• Significant genotype frequency differences were found between AD and controls, AD and Parkinson's disease (PD), and AD and Down's syndrome (DS).

Conclusions:

• The study suggests that an increased frequency of the ApoE epsilon 4 allele is associated not only with Alzheimer's disease (AD) but also with other dementing neurological disorders.
• These findings indicate a potential broader role for ApoE epsilon 4 in the pathogenesis of various neurodegenerative conditions.