["Research focusing on the role of APOE in Parkinson's disease (PD) has been largely inconclusive, creating a broad discrepancy in association studies.", 'To elucidate the role of APOE alleles in PD risk by studying a large sample size and controlling for population substructure.', 'In total, 3465 case and control samples were genotyped, obtained from the NINDS Neurogenetics repository.', 'No significant differences in ε4 dosages exist between PD cases and controls. The frequency of ε4 carriers differed slightly between cases and controls at 24% (580/2412) and 26% (270/1053), respectively. Likewise, mean dosages of APOE ε2 were not significantly different between cases and controls. APOE ε2 carriers were observed at a frequency of 13.6% (329/2412) among cases and 15% (158/1053) among controls. Logistic regression models evaluating PD as possibly associated with ε4 or ε2 carrier status and allele dosages yielded no significant results. The mean MMSE score among all PD cases was 28.35 (SD = 2.58) and memory loss was reported in only 11.9% (105/879) of cases. Linear regression models comparing MMSE scores as predicted by ε4 or ε2 carrier status and allele dosages were not significant.'] Does a large study reveal no association between APOE and Parkinson 's disease?