Apolipoprotein E (Αpo-Ε) has attracted considerable interest due to its possible implication in the pathogenesis of various neurodegenerative disorders.The Αpo-Ε gene, located on chromosome 19, is polymorphic, with ε2, ε3, ε4 being the most common alleles. Since the Αpo-Ε ε4 allele has been associated with increased risk for the development of Alzheimer’s disease, a number of investigators attempted to explore the role of Αpo-Ε genotypes in various movement disorders of degenerative origin such as Parkinson’s disease (PD), Lewy body dementia (LBD), progressive supranuclear palsy (PSP), multiple system atrophy (MSA) etc.
The main stream of research in this field involves PD, yet the various reports are conflicting. Some investigators have found a relation between the Αpo-Ε ε4 allele and PD,while others have not. There are also reports involving the ε2 allele with an increased risk of PD. In some studies an association between the Αpo-Ε ε4 allele and dementia in PD seemed plausible, but others favor instead an association of the ε2 allele with dementia.
In LBD the Αpo-Ε ε4 allele seemed to occur more frequently, but there are also studies implicating the ε2 allele, too. Αpo-Ε allele status has not been shown to influence the development of PSP or MSA. Correlation of Αpo-Ε genotypes and corticobasal ganglionic degeneration yielded conflicting results. In Wilson’s disease the distribution of Αpo-Ε genotypes was the same as in general population, but the ε3/ε3 genotype was related to a delayed onset of symptoms.
In conclusion, the way Αpo-Ε genotypes influence the onset and progression of various movement disorders remains uncertain.