Relationship between the Apolipoprotein AI, B gene polymorphism and the risk of non-traumatic osteonecrosis

Abstract

Background: Previous studies suggested that Apolipoprotein AI (ApoAI) and apolipoprotein B (ApoB) gene polymorphisms may result in lipid metabolism disorders. Genetic polymorphisms in these genes may be associated with the occurrence of osteonecrosis.

Methods: We designed a case-control study including 429 patients of osteonecrosis and 368 age- and sex-matched control subjects. Polymerase chain reaction was used to amplify the DNA fragments in promoter -75 G > A of ApoAI gene and EcoR I, Xba I and 3'-VNTR of ApoB gene in osteonecrosis patients and healthy controls. We utilized polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method to genotype these four single nucleotide polymorphisms (SNPs).

Results: For -75 G > A polymorphism of ApoAI, AA genotype frequency (0.501) was significantly higher in patients with osteonecrosis than that in control (0.462) subjects (P <0.001), GA genotype frequency (0.170) was significantly lower than that in the control (0.310) group (P <0.0001). In osteonecrosis patients, the odds ratio (OR) of A allele was 3.932 (95% CI: 3.0847 ~ 5.0123), which suggested that subjects carrying A allele of promoter region -75 G > A of ApoAI gene had higher susceptibility to osteonecrosis than G allele carriers. The genotype and allele frequency distributions showed no significant difference in EcoR I, Xba Iand 3'-VNTR loci of ApoB gene between the osteonecrosis group and control group.

Conclusion: Our study suggested that ApoAI gene -75G > A polymorphism may be associated with susceptibility to osteonecrosis in Chinese population. However, our results need further investigation with large sample size and various populations.

Figure 1

Gel electrophoresis images by PCR-RFLP method. The genotyping results: A: -75 G > A of ApoAI gene, 1, 3 GG; 2,4: GA, 5: AA. B: EcoR I loci of ApoB gene: 1,3,4: E + E+, 2:E + E-; C: XbaI loci of ApoB gene: 1, 3: X-X-; 2,4: X + X-; D: 3′-VNTR of ApoB gene. 1,2: SB, 3,4: SS.