ADD1 and Hypertension: Furthermore, additional SNP in candidate genes listed in Table 4 has been shown to influence HCTZ response in hypertensive patients and include alpha-adducin (ADD1; T allele carriers responded better to low-dose diuretic therapy) [56], rs5051 SNP in the promoter of the angiotensin gene (AGT) and the linkage with rs699, which results in a M235T variant, also referred to as C4072T, has been associated with an increased risk of hypertension in African-Americans compared to Caucasians.