The impact of Apolipoprotein E alleles on cognitive performance in patients with Parkinson's disease

Apolipoprotein E (ApoE) is a vital component of several lipoproteins and plays a major role in lipid metabolism. APOE gene comprises of three alleles determined by two single nucleotide polymorphisms (rs429358 and rs7412) resulting in the protein isoforms, among which ApoE4 is a confirmed risk factor for Alzheimer's Disease. However, the impact of APOE genotypes on Parkinson's Disease Dementia (PDD) is still inconclusive. The PDD diagnostic criteria are very inconsistent, and could be complemented with genetic factors. Our study covers a total of 237 patients diagnosed with Parkinson's Disease (PD) according to UK PD Brain Bank criteria, who were classified as subjects with (PDD, n equals 73) and without (nPDD, n equals 164) dementia, using neuropsychological assessment tests. TaqMan real-time PCR assays were used to determine APOE allele. No statistically significant differences in APOE alleles frequencies between nPDD and PDD patients have been observed. The study results revealed that the APOE polymorphism is not associated with cognitive status in PD patients.