316 ORIGINAL ARTICLE Association of endothelial nitric oxide synthase gene (G894T) polymorphism and hypertension in diabetic Bataknese patients Jelita Siregar 1 , Ratna Akbari Ganie 1 , Dharma Lindarto 2 , Erna Mutiara 3 , Delfitri Munir 4 1 Department of Clinical Pathology, 2 Department of Internal Medicine, 3 Department of Population and Biostatistics, 4 Department of Otorhinolaryngology, Head and Neck Surgery; School of Medicine, Universitas Sumatera Utara, Medan, Indonesia Corresponding author: Jelita Siregar Department of Clinical Pathology, School of Medicine, Universitas Sumatera Utara dr. Mansyur 5, Medan, Indonesia Phone: +62 61 821 1045; Fax: +62 61 821 6264; E-mail: jelitasiregar1978@gmail.com ORCID ID: https://orcid.org/0000-0002- 6054-913X Original submission: 11 October 2019; Revised submission: 20 January 2020; Accepted: 21 February 2019 doi: 10.17392/1088-20 Med Glas (Zenica) 2020; 17(2): 316-320 ABSTRACT Aim To assess endothelial nitric oxide synthase (eNOS) gene (G894T) polymorphism and nitric oxide (NO) level in hypertensi- ve diabetic Bataknese patients. Methods A hospital-based, case control study (hypertensive and normotensive diabetic patient) was conducted. Genotyping of eNOS gene (G894T) was done using polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP). Nitric oxide was quantifed by sandwich enzyme-linked immunosorbent assay (Sandwich ELISA). Results GT polymorphism and T allele were higher in the hy- pertensive diabetic patients, 37.5% (p=0.6) and 54% (p=0.39), respectively. Nitric oxide level tended to be lower in the hyperten- sive diabetic patients (88.87µmol/L) comparing to the normoten- sive (95.42 µmol/L (p=0.54), as well as GT and TT polymorphism type (p=0.75). Conclusion eNOS gene (G894T) polymorphism is not associated with NO level and hypertension in the diabetic Bataknese patients. Key words: diabetes mellitus, hypertension, nitric oxide, nitric oxide synthase type III, polymorphism