THE APOLIPOPROTEIN-E EPSILON-4 ALLELE IN PARKINSONS-DISEASE WITH ALZHEIMER LESIONS

The association between the apolipoprotein E (ApoE) epsilon 4 allele a nd Parkinson's disease (PD) with coexistent dementia has remained cont roversial. We determined ApoE allele frequencies in 35 subjects with n europathologically confirmed Lewy body Parkinsonism with and without c oncomitant Alzheimer lesions, 27 patients with Alzheimer's disease (AD ), and 54 controls without neurodegenerative disease. We hypothesized that if AD lesions in PD evolve by the same pathomechanism as in ''pur e AD,'' the ApoE epsilon 4 allele frequency in PD with AD lesions (PD + AD) and pure AD should be similar. The frequency of the ApoE epsilon 4 allele differed significantly between PD + AD (13,3%) and AD cases (35,2%), but not between PD + AD and PD without AD pathology (12,5%) o r controls (11,1%). We conclude that the ApoE epsilon 4 allele does no t function as a risk factor which influences the development of AD les ions in PD. Our data suggest that Parkinson's disease with Alzheimer l esions and Alzheimer's disease with coexistent Parkinsonian features r epresent two distinct entities at both the clinicopathological and mol ecular genetic levels. (C) 1996 Academic Press, Inc.