[The association between polymorphism of endothelial nitric oxide synthase gene and cirrhotic portal hypertension].

OBJECTIVE: To study whether the liver cirrhosis and portal hypertension are associated with a -786T-->C mutation at promoter and VNTR polymorphism in intron 4 and a 894 G-->T mutation at exon 7 of the eNOS. METHODS: A case control study of 106 patients with liver cirrhosis due to HBV was performed in comparison with 108 controls with the help of PCR-SSCP or RFLP. RESULTS: There was no difference in the gene frequency of allele G of promoter between LC(+) group and other groups. The frequencies of the T and TG genotype at exon7 and the a allele and ab genotype in intron 4 were significantly higher in portal hypertension group (LC(+)) than in liver cirrhosis group alone and control group (P < 0.05). Patients of the liver cirrhosis with coexistence of the T and a alleles had a higher incidence of portal hypertension (P < 0.05) than those with only one of the two alleles or without any of the two alleles. Multivariate logistic regression analysis revealed that VNTR polymorphism in intron 4 and 894 G-->T mutation at exon 7 of the eNOS gene are independent risk factors for the occurrence of portal hypertension in patients with liver cirrhosis. CONCLUSION: The T allele at exon 7 and a allele in intron 4 are associated with the occurrence of portal hypertension in patients with liver cirrhosis. The ocurrence of portal hypertension with liver cirrhosis is higher in patients who have both T and a allele than patients who have either T or a allele alone, which is an independent risk in occurrence of portal hypertension, respectively. TGab may be susceptibility genotype of portal hypertension.