[Relationship between gene polymorphism at the apolipoprotein E locus and serum lipid profile in urban children of school age in Beijing].

OBJECTIVE: To study the relationship between gene polymorphism at the apolipoprotein E (ApoE) locus and serum lipid levels in children of school age.
METHODS: Blood samples were collected from 307 normal children aged 7 to 11 years, including 150 boys and 157 girls, and their serum lipid profile, including total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), apolipoprotein B(apoB), apoprotein A1 (ApoA I) and lipoptoein alpha[LP (alpha)], were detected and their ApoE-Hha I gene polymorphism were tested by the PCR-RFLP method.
RESULTS: The detection rates for the most frequent genotype ApoE3/3 was 54.7%, other genotypes E4/3, E4/4, E3/2, E4/2 and E2/2 were 23.8%, 9.1%, 8.1%, 3.9% and 0.3%, respectively, in 307 children, with no significant difference between girls and boys(P > 0.05). Frequency of the often seen allele E3 was 70.7%, and that of E4 and E2 was 23.0% and 6.4, respectively, with E4 significantly higher than and E2 similar to that in the other domestic reports. The levels of TC, LDL-C, ApoA I and ApoB were higher in boys with genotypes E4/3 and E3/3 than those with genotypes E3/2 and E4/2. Levels of TC and ApoA I in the boys with genotype E3/2 were higher, with TC of 4.28 mmol/L and ApoA I of 3.41 mmol/L. There were no significant difference in serum lipid levels of girls with different genotypes(P > 0.05). There also was no significant difference in the ApoE-Hha I genotype distribution between normal children and those with high TC. ApoE2 could decrease the level of TC by 0.377 mmol/L, and LDL-C by 0.329 mmol/L.
CONCLUSIONS: Serum level of TC associated with polymorphism of ApoE gene carrier in boys, with the lowest levels of TC, LDL-C and ApoE in three with allele E2.