Genome-Wide Gene-Potassium Interaction Analyses on Blood Pressure: The GenSalt Study (Genetic Epidemiology Network of Salt Sensitivity).

Abstract

Background: Gene-environmental interaction analysis can identify novel genetic factors for blood pressure (BP). We performed genome-wide analyses to identify genomic loci that interact with potassium to influence BP using single-marker (1 and 2 df joint tests) and gene-based tests among Chinese participants of the GenSalt study (Genetic Epidemiology Network of Salt Sensitivity).

Methods and results: Among 1876 GenSalt participants, the average of 3 urine samples was used to estimate potassium excretion. Nine BP measurements were taken using a random-zero sphygmomanometer. A total of 2.2 million single nucleotide polymorphisms were imputed using Affymetrix 6.0 genotype data and the Chinese Han of Beijing and Japanese of Tokyo HapMap reference panel. Promising findings (P<1.00×10^-4) from GenSalt were evaluated for replication among 775 Chinese participants of the MESA (Multi-ethnic Study of Atherosclerosis). Single nucleotide polymorphism and gene-based results were meta-analyzed across the GenSalt and MESA studies to determine genome-wide significance. The 1 df tests identified interactions for ARL15 rs16882447 on systolic BP (P=2.83×10^-9) and RANBP3L rs958929 on pulse pressure (P=1.58×10^-8). The 2 df tests confirmed the ARL15 rs16882447 signal for systolic BP (P=1.15×10^-9). Genome-wide gene-based analysis identified CC2D2A (P=2.59×10^-7) at 4p15.32 and BNC2 (P=4.49×10^-10) at 9p22.2 for systolic BP, GGNBP1 (P=1.18×10^-8), and LINC00336 (P=1.36×10^-8) at 6p21 for diastolic BP, DAB1 (P=1.05×10^-13) at 1p32.2, and MIR4466 (P=5.34×10^-8) at 6q25.3 for pulse pressure. The BNC2 (P=3.57×10^-8) gene was also significant for mean arterial pressure.

Conclusions: We identified 2 novel BP loci and 6 genes through the examination of single nucleotide polymorphism- and gene-based interactions with potassium.