Frequencies of apolipoproteins E5 and E7 in apparently healthy Japanese

Abstract

SummaryHuman apolipoprotein (apo) E plays an important role in the metabolism of cholesterol and other lipids. Apo E5 and apo E7 are genetic variants of apo E and have been detected in about 5~ of Japanese patients with hyperlipidemia and ischemic heart disease. The existence of apo E5 and apo E7, however, had not been reported in apparently healthy individuals except for a few family members of the patients with apo E5 or apo E7. It has been suggested that apo E5 and apo E7 are closely related to the development of atherosclerosis. The purpose of this study is to investigate the frequency of apo E5 and apo E7 in apparently healthy Japanese and to analyze serum lipid levels of the individuals with apo E5 or apo E7.The apo E phenotypes of 197 apparently healthy Japanese adults were determined by two-dimensional gel electrophoresis. The gene frequencies ofapo E were: ~3, 0.843; ~4, 0.112; ~2, 0.038; e5, 0.006; ~7, 0.0035. Three out of 187 subjects (1.5~) were found to have apo E5 or apo E7 in heterozygous state. Two of them were heterozygous with apo E3 (apo E3/5 and apo E3/7) and the both had normal serum lipid levels, though they were more than 50 years old. The other individual was heterozygous with apo E2 (apo E2/5) and had mild hypertriglyceridemia. As to myocardial infarction, angina pectoris and cerebral infarction, no clinically abnormal findings were detected in all the three individuals with apo E5 or apo E7.The data suggest that the frequency of the individuals with apo E5 or apo E7 is of the order of 1 X and much higher than that of the homozygotes with apo E2/2 in Japanese. The data also indicate that further genetic, epidemiologic and clinical studies are required to determine whether ~5 and ~7 act as a dominant major gene, as a recessive major gene, or as

Apolipoprotein e phenotypes and serum lipid levels in apparently healthy male adults in Tokyo

“…Two subjects with the apo E2/3 phenotype were normolipidemic. The one subject with the apo E2/5 phenotype had a mild degree of hypertriglyceridemia, as described elsewhere (Tsuchiya et al, 1985).…”

“…Their mean (• age was 47.1+_7.1 (range 35-64). The phenotypes of apo E was determined by two-dimensional gel electrophoresis as described previously (Tsuchiya et al, 1985). Serum total cholesterol and triglyceride were measured enzymatically (Allain et al, 1974;Sampson et aL, 1975) on an automated analyzer (Hitachi Model 712, Hitachi Ltd., Tokyo).…”

Association of the apolipoprotein E4 allele with hypercholesterolemia in apparently healthy male adults in Tokyo

“…The phenotype of apo E was determined by two-dimensional gel electrophoresis as described previously (Tsuchiya et al, 1985). Serum total cholesterol and triglyceride were measured enzymatically (Allain et al, 1974;Sampson et al, 1975) on an automated analyzer (Hitachi Model 712, Hitachi Ltd., Tokyo).…”

“…In the apo E gene, there are three common alleles, designated s2, s3 and s4, which code for apo E2, apo E3, and E4, respectively (Zannis et al, 1982). The apo E3 allele is the most common and the apo E4 allele is the second commonest in Japanese (Asakawa et al, 1985;Tsuchiya et al, 1985;Eto et al, 1986). The apo E4 allele is present in about 20~ of populations.…”

Apolipoprotein E5 and E7 in apparently healthy Japanese males: Frequencies and relation to plasma lipid levels

“…Further-more, a novel apo E5 derived from E3 by a Glu~Lys substitution at position 13 [E5(Gluls~Lys)] and another novel apo E5 derived from E4 by a Pro--,Arg substitution at position 84 [E5(Proa4~Arg, CySll~--,Arg)] were discovered in two FrenchCanadian subjects (Mailly et al, 1991) and in a subject of European descent (Wardell et al, 1991), respectively; On the other hand, Apo E7 is derived from E3 by a Glu~Lys substitution at positions 244 and 245 [E7(Gluz44,245---,Lys)] (Maeda et al, 1989b;Tajima et al, 1989). Thus far, apo E7 has been detected only among Japanese (Yamamura et al, 1984a, b;Tsuchiya et al, 1985). As for apo E5 and E7, there are no reports regarding their frequencies and relations with plasma lipid levels in general populations.…”