title: Endothelial nitric oxide synthase gene polymorphism and type 2 diabetic retinopathy among Asian Indians.
abstract: Endothelial nitric oxide synthase (eNOS) has been shown to play an essential role in retinal vascular function, and disequilibrium in its production can lead to diabetic retinopathy (DR). Genetic polymorphisms of eNOS gene have been suggested to play a role in nitric oxide (NO) abnormalities which may contribute to the development and progression of DR. In view of the variable results that have been reported for the association between eNOS gene polymorphisms and DR, the present study was designed to study the association and interaction between eNOS gene polymorphisms and the development and progression of DR in Asian Indian type 2 diabetes mellitus patients (T2DM). We screened 1,720 T2DM patients, belonging to two independently ascertained cohorts out of which 1,446 were genotyped for three polymorphisms of eNOS (two SNPs: T-786C, G894T and one 27-bp repeat polymorphism in intron 4 (27VNTR)) using validated PCR-RFLP assays. In both the cohorts, consistently lower prevalence and decreased risk of DR was observed in patients with ba, aa and ba + aa genotype of 27VNTR (a/b), C-a-G and C-a-T haplotype (allele of T-786C, 27VNTR a/b and G894T) carrying "C" allele of T-786C and "a" allele of 27VNTR (a/b). Also, mean NO levels in T2DM subjects carrying ba + aa genotype were higher as compared to bb genotype. Our results suggest that eNOS genotypes 27VNTR carrying "aa" genotype is an independent protective factor for DR and is associated with low risk of DR.
authors.affiliation: Department of Experimental Medicine and Biotechnology, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Balneek Singh
authors.initials: BS
authors.lastname: Cheema
authors.forename: Harbir Singh
authors.initials: HS
authors.lastname: kohli
authors.forename: Rajni
authors.initials: R
authors.lastname: Sharma
authors.forename: Anil
authors.initials: A
authors.lastname: Bhansali
authors.forename: Madhu
authors.initials: M
authors.lastname: Khullar
mesh_terms: D044466:Asian People / Q000706:statistics & numerical data; D016022:Case-Control Studies; D015331:Cohort Studies; D004252:DNA Mutational Analysis; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000208:ethnology / Q000235:genetics*; D003930:Diabetic Retinopathy / Q000208:ethnology / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D018598:Minisatellite Repeats / Q000235:genetics; D052250:Nitric Oxide Synthase Type III / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000502:physiology; D020641:Polymorphism, Single Nucleotide; D054928:Validation Studies as Topic
chemical_list: C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III