Many studies have been performed to investigate an association of genetic polymorphism and DVT. A case–control study found that subjects carrying endothelial protein C receptor (EPCR) gene 6936AG genotype likely had an increased risk of DVT . The 20210 A allele of the prothrombin gene was a common risk factor among Swedish outpatients with verified DVT . A case control study found an excess of rare coding single-nucleotide variants of the ADAMTS13 gene in patients with DVT . A homozygosity state for 20210A prothrombin variant in a young woman was a cause of DVT during pregnancy . Susceptibility to DVT in North Indian Asian patients may be associated with some variants of nitric oxide synthase 3 (NOS3) gene . A large case–control study found that factor XIII (FXIII) 34Leu carriers were associated with a slightly decreased DVT risk . A case control study found that genetic variants in the F11 gene were risk factors for DVT among both Whites and Blacks . A meta-analysis indicated that rs2227589 in the SERPINC1 gene, rs13146272 in the CYP4V2 gene and rs1613662 in the GP6 gene were risk factors for DVT among Whites . A case control study concluded that the G534E-polymorphism of the gene encoding the factor VII-activating protease is a risk factor for DVT . A case control study suggested that tumor necrosis factor alpha (TNF-alpha) -308A allele was association with the risk of DVT . The rs4524 SNP in F5 was consistently associated with DVT in 3 large case–control studies . A case control study suggested that factor V G1691A (Leiden) and A4070G (HR2 Haplotype) polymorphisms were independent risk factors for DVT [31, 32].
The APOE gene polymorphisms were associated with many other diseases. The E4 allele of the APOE gene was associated with a worse lipid profile in the Brazilian urban population . In the Tunisian population the APOE E4 appears to be only indirectly involved in the severity of coronary artery disease . E2 allele of the APOE gene polymorphism was predictive for obesity status in Roma minority population of Croatia . A meta-analysis included 29 studies involving 2,737 CI cases and 2,689 controls suggested that APOE E4 allele was associated with an increased risk of developing cerebral infarction in Chinese population . A meta-analysis of 45 studies including 13,940 cases and 16,364 controls found that APOE gene polymorphisms were associated with essential hypertension . A meta-analysis of 28 case–control studies provided evidence for an association between the APOE E4 allele and frontotemporal lobar degeneration . A meta-analysis of seven studies, including 2,090 cases and 742 control suggested an association between APOE E4 mutation and increased risk of recurrent pregnancy loss . A meta-analysis of seven studies with 966 patients and 1,086 controls suggested that the APOE polymorphisms were assoated with the risk of psoriasis, especially E2 and E3 alleles . A meta-analysis of experimental and human studies suggested an association between APOE gene expression and its gene polymorphism with nephrotic syndrome susceptibility . A meta-analysis of 6977 subjects provides evidence that APOE E2 mutation is associated with multiple sclerosis risk . A meta-analysis of 29 studies included 1,763 cases and 4,534 controls provided evidence for an association between APOE gene polymorphisms and the risk of vascular dementia . A meta-analysis of 17 studies, including 1,773 cases and 2,751 controls, revealed that APOE gene E4 allele was a risk factor of gallbladder stone disease, especially in elder people and Chinese population .
Some limitations of this study should be noted. First of all, this is a hospital based case control study, so the selection bias cannot be avoidable and the subjects may not be representative of the general population. Second, the sample size of this study is relatively small, which may not have enough statistical power to explore the real association. Third, these results should be interpreted with caution because the population was only from China, which reduces the possibility of confounding from ethnicity, so it does not permit extrapolation of the results to other ethnic groups.