None of the family members carrying APOE*3-(Cys-112-->Arg; Arg-251-->Gly) and/or APOE*2(Val-236-->Glu) exhibited lipoprotein abnormalities characteristic of familial dysbetalipoproteinaemia, although three family members carrying APOE*3-(Cys-112-->Arg; Arg-251-->Gly) showed hypertriglyceridaemia.
Dominant expression of type III hyperlipoproteinemia associated with apoE phenotype E3/3 is caused by heterozygosity for a human apoE variant, apoE3(Cys112----Arg, Arg142----Cys).
This explains the significant effect of the apoE gene locus on the variability of plasma lipoprotein concentrations and moreover the implication of apoE alleles in the aetiology of multifactorial forms of hyperlipidaemia e.g. familial type III hyperlipidaemia (apoE2; arg158----cys) and polygenic hypercholesterolaemia (apoE4; cys112----arg).