Association of endothelial nitric oxide synthase polymorphisms in primary biliary cirrhosis (PBC) patients and first degree relatives (FDR) of cretan origin

Introduction and background Twin and family studies suggest that there is a significant heritable component to PBC. It has been suggested that increased nitric oxide (NO) synthesis may contribute to the development of the hyperdynamic circulation observed in cirrhotic patients, while total NO circulating levels are enhanced in PBC. Aims The authors examined two endothelial nitric oxide synthase (eNOS) gene polymorphisms, a 27-bp repeat in intron 4 and a Glu298Asp in exon 7, to assess a possible association with the development of PBC in a genetically homogenous Cretan population. Methods Genomic DNA was extracted from 91 PBC patients (77 female), 82 AMA+, median age 68 years (41–84 years), 48/91 Ludwig stage I–II and 101 FDR (63 female), median age 41 (age range 18–80 years), 3/101 AMA+ and 20/101 ANA+ of Cretan origin. 100 sex, age and geography matched healthy controls (76 female), median age 69 years (39–86 years), 9/100 ANA+. Exon7 polymorphism was determined by PCR–restriction fragment–length polymorphism analysis. Intron4 polymorphism was determined using PCR amplification with oligonucleotide primers. Distribution of genotypes and alleles was compared by x 2 test or Fisher9s exact test. Conclusions In Cretan PBC patients both eNOs intron 4 VNTR and Glu298Asp in exon 7 eNOs polymorphism are not associated with disease occurrence or disease stage.