POPULATION FREQUENCY OF APOLIPOPROTEIN E5 (GLU3-]LYS) AND E7 (GLU244-]LYS, GLU245-]LYS) VARIANTS IN WESTERN JAPAN

Apolipoprotein (ape) E modulates the catabolism of chylomicrons and of very low density lipoprotein remnants. It has three major isoforms (a pe E2, E3, E4) and some rare variants. To detect the variants of apo E , blood specimens from 1269 Japanese subjects were analyzed using isoe lectric focusing with immunoblotting. The E5 and E7 variants were iden tified by IEF in 2 and 18 subjects, respectively. Both E5 (Glu3-->Lys) carriers were confirmed by PCR-mediated site-directed mutagenesis, an d all E7 (Glu244-->Lys, Glu245-->Lys) carriers were confirmed by the a mplification refractory mutation system. The relative frequencies of t he E5 and E7 alleles were 0.001 and 0.007, respectively. High concentr ations of total cholesterol (>220 mg/dl) were detected in five of the subjects expressing apo E7 and one subject expressing apo E5, and eigh t subjects heterozygous for apo E7 showed elevated plasma triglyceride concentrations (>150 mg/dl). In 621 healthy subjects, the mean trigly ceride concentration in subjects with apo E7/3 appeared to be higher t han in those with apo E3/3, but the difference was not statistically s ignificant.