Apolipoprotein E polymorphism and its association with serum lipoprotein concentrations in black versus white...

The structural gene locus for apolipoprotein E (apo E) is polymorphic. The relative apo E allele frequencies and the influence of this polymorphism on serum lipoprotein concentrations were studied in 8- to 17-year-old black (n = 444) and white (n = 446) children from the community of Bogalusa, LA. The frequencies of the e2, e3, and e4 alleles for white males/females were 0.027/0.024, 0.849/0.823, and 0.124/0.153, respectively; corresponding values for black males/females were 0.087/0.074, 0.713/0.721, and 0.20/0.205, respectively. Apo E phenotype distributions and allele frequencies showed a significant race difference, but no sex difference. Significant differences among apo E phenotypes were noted for total cholesterol, low-density lipoprotein cholesterol (LDL-C), and apo B in both races; significant effects were noted for high-density lipoprotein cholesterol (HDL-C) and apo A-I in black children, but not in white children. Among white children, the average excess of the apo e2 allele showed lower LDL-C (-12.5 mg/dL) and apo B (-15.8 mg/dL) concentrations, while the average excess of the apo e4 allele showed higher LDL-C (7.0 mg/dL) and apo B (7.5 mg/dL) concentrations. Black children showed a similar trend for these variables, but to a lesser degree; in addition, the average excess of apo e2 allele showed higher HDL-C (12.8 mg/dL) and apo A-I (8.3 mg/dL) concentrations in this racial group. It is noteworthy that the association of apo E polymorphism with serum lipoprotein concentrations noted in adults can be seen already in children.