Apolipoprotein E genotypes in AA and AL amyloidoses

Apolipoprotein E (apoE) is associated with senile plaques in Alzheimer's disease (AD), and present in amyloid deposits in a variety of systemic amyloidoses. Recently, studies have shown that apoE4 allelic frequency is increased in patients with sporadic and familial late-onset AD and that apoE4 may represent a susceptibility gene for late-onset AD. We addressed the issue of whether a similar association of apoE4 exists in a number of systemic amyloidoses. Tissue was obtained from control subjects, AD patients, familial Mediterranean fever (FMF) patients, amyloid A (AA) amyloid secondary to juvenile chronic arthritis (JCA), and amyloid of the light chain type (myeloma or AL). There was a strong correlation of the apoE4 allele with sporadic and late-onset AD, but no significant increase in apoE4 with other amyloidoses. These data suggest that whereas apoE4 may be a risk factor in AD, it is not in other amyloidoses. However, given the association of apoE with all these amyloidoses, the possibility cannot be ...