FRI153 Genetic Variant In Armadillo Repeat Containing 5 Gene (ARMC5) Associates With Salt Sensitivity Of Blood Pressure And Aldosterone In A Caucasian Cohort

Disclosure: W.W. Parksook: None. M. Heydarpour: None. L. Pojoga: None. A. Gaye: None. G.H. Gibbons: None. G.H. Williams: Advisory Board Member; Self; Cereno. Consulting Fee; Self; Alnylam, Crinetics, Damian, KBP bioscience, Paxel, Relapsa, Unicycive. Grant Recipient; Self; NIH 2 grants. J.S. Williams: Advisory Board Member; Self; Mellicell, Inc. Background: Genetic alterations of ARMC5 have been reported in various adrenal disorders, particularly in primary bilateral macronodular adrenal hyperplasia. Increasing evidence shows that polymorphic variants in ARMC5 are also associated with blood pressure (BP), hypertension, and the renin-angiotensin-aldosterone-system (RAAS) in individuals of African descent; however, little is known about these relationships in Caucasians. Herein, we conducted a deep phenotyping study to assess the association of ARMC5 variants with BP, salt sensitivity of BP (SSBP), and components of the RAAS in Caucasians. Methods: Normotensive and hypertensive, non-diabetic, non-chronic kidney disease, Caucasian participants underwent two dietary interventions at 5-7 days apart (200 mmol/day and 10 mmol/day sodium) to assess SSBP and other hormonal parameters. All participants were genotyped using a Multi-Ethnic-Genotyping-Array. Association analysis and the quality control of the genomic data were assessed by PLINK. Participants with complete data for SSBP and hormonal parameters, who were in salt balance, were included in the analysis (n= 306). Multiple linear regression models were used to assess the association between the genetic variant and outcome parameters. Results: There were 5 single nucleotide polymorphisms in the ARMC5 region. rs4889660 was significantly associated with SSBP in additive and dominant models when adjusted by Bonferroni correction. In a candidate gene analysis, rs4889660 risk allele carriers had greater SSBP than non-risk allele homozygotes (β= 4 mmHg, P= 0.03). Following dietary sodium restriction, rs4889660 risk allele carriers had lower serum aldosterone levels in an upright position (β= -6.9 ng/dl, P= 0.04) and serum aldosterone levels after angiotensin II stimulation (β= -3.0 ng/dl, P= 0.02). There were no differences between plasma renin activity, serum and urinary cortisol levels, and renal plasma flows between genotypes. Conclusions: There was an association between the ARMC5 rs4889660 variant and SSBP in Caucasians. With dietary sodium restriction, aldosterone responses to both upright posture and angiotensin II infusion were lower in the risk allele carriers. The reduced aldosterone responses suggest that an alteration in the RAAS system is not the cause of the SSBP, but is in response to a defect in another sodium-mediated homeostatic mechanism. Presentation: Friday, June 16, 2023