Role of Apolipoprotein E in the Clinical Profile of Atypical Parkinsonian Syndromes.

Abstract

Atypical Parkinsonian syndromes (APS) encompass a spectrum of neurodegenerative diseases including dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), multiple system atrophy (MSA), and corticobasal syndrome (CBS). The effects of the Apolipoprotein E (APOE) gene on APS clinical features are controversial and understudied in several populations. We aimed to explore the influence of APOE genotype on clinical features in an APS Tunisian cohort. We included clinically diagnosed APS patients genotyped for APOE, and analyzed the clinical and APOE genotype associations. A total of 328 APS patients were included, comprising 184 DLB, 58 PSP, 49 MSA, and 37 CBS. Significant differences in initial Mini-Mental State Examination and Frontal Assessment Battery scores according to APOE genotypes (P=0.05 and 0.0048) were found. Executive dysfunction (P=0.026) disorientation (P=0.025), and hallucinations (P<0.001) were more pronounced among APOE-ɛ4 carriers particularly in DLB. Memory disorders were also correlated to APOE-ɛ4 allele (P=0.048) and were more frequent among DLB and PSP carriers. Depression was associated to APOE-ε4 (P=0.042), more markedly in APOE-ε4-CBS and MSA carriers. Our findings suggested a role of APOE-ε4 in defining a more altered cognitive phenotype with variable degrees across subgroups in APS patients, especially in DLB carriers. This effect mainly concerned executive, memory and orientation functions as well as hallucinations.