Discovery of common human genetic variants of GTP cyclohydrolase 1 (GCH1) governing nitric oxide, autonomic activity, and cardiovascular risk
J. Clin. Invest. 117:9 doi:10.1172/JCI31093 [Go to this article.]

Figure 3
GCH1 3′-UTRs (C+243T) polymorphism effects on biochemical and physiological traits in twin pairs.

(A) Baroreflex coupling as a function of renal NO (NO•) production. Univariate effects of C+243T on each trait are shown. Baroreflex coupling was determined in the low-frequency domain (0.05–0.15 Hz). Renal NO production was normalized to the concentration of creatinine in the same urine sample. Univariate NO: χ² = 9.50, P = 0.0086. Univariate baroreflex: χ² = 6.37, P = 0. 0414. Alleles: C = 80.2%, T = 19.8%. Hardy-Weinberg equilibrium (HWE), χ² = 1.76, P = 0.184. (B) Minimum resting heart rate as a function of heart rate variability. Univariate effects of C+243T on each trait are shown. Heart rate variability, in the resting state, was determined as pulse interval (PI) SD (ms) over 5 minutes of monitoring in the time domain. Minimum resting heart rate was determined as maximum (max) PI (ms) during the same monitoring period. Univariate PI SD: χ² = 6.0, P = 0.0498. Univariate PI max: χ² = 9.78, P = 0. 0075. Alleles: C = 80.2%, T = 19.8%. HWE, χ² = 1.76, P = 0.184.