Apolipoprotein E Polymorphism in a Healthy Lebanese Population
Objective: The gene for apolipoprotein (apo) E, which modulates serum lipoprotein metabolism and concentration, is polymorphic with three major alleles, E2, E3, and E4, and a corresponding six apo E genotypes, E2/E2, E3/E2, E3/E3, E4/E2, E4/E3, and E4/E4. Due to its clinical importance in regulating lipid transport and redistribution, and coupled with the association of certain apo E alleles with metabolic disorders, we investigated apo E genotype in 155 healthy Lebanese individuals of both sexes, aged 5–77, by PCR/Cfo I restriction analysis. Methods: Total genomic DNA was extracted from the peripheral blood of study subjects, and apo E genomic sequence was amplified by PCR using one set of primers defining a conserved region of apo E gene. Apo E genotype was determined by the digestion of the PCR products with Cfo I, followed by agarose gel electrophoresis. Results: Among the genotypes obtained the most prevalent were: E3/E3 (120/155; 77.42%), E2/E3 (20/155; 12.90%), E3/E4 (13/155; 8.39%), and E2/E4 (2/155; 1.29%). None of the homozygous E2/E2 or E4/E4 genotypes were detected. Furthermore, there was no difference in apo E genotype distribution with regard to age or sex, which is in accordance with the reports for other study populations. Conclusions: The finding that apo E3/E3 is the most significant genotype in healthy Lebanese is similar to what was described for Caucasian populations. Further studies are required to establish the prevalence of homozygous E2/E2 and E4/E4.