It has been shown that the Apolipoprotein E (ApoE) epsilon4 allele increases the risk of developing Alzheimer's disease (AD) and lowers the age of its onset. ApoE has also been suggested to be a common facilitating factor in the different types of amyloidoses. However, the association of ApoE epsilon4 with the onset of disease in various types of amyloidoses has not been extensively investigated. Type I familial amyloid polyneuropathy (FAP) is one form of systemic amyloidosis in which ApoE co-localizes with amyloid deposits. We examined 54 patients with type I FAP and found that there was no significant effect of either ApoE epsilon2 or epsilon4 allele on the age at onset. Our results suggest that ApoE4 is not a facilitating factor in the development of FAP, transthyretin amyloidosis.