DDAH1 and hypertensive disorder: 17 G > C) in DDAH1 was a risk factor for hypertension in the Kazakh group in the co-dominant model (G/C versus G/G) (OR = 1.39; 95% CI = 1.02-1.88; P < 0.05) and the same result was obtained in the dominant model (G/C + C/C versus G/G) (OR = 1.38; 95% CI = 1.03-1.84; P < 0.05).