Table 5.
Genetic marker-on-trait associations between DDC coding variant Arg462Gln (rs11575542, G > A) and phenotypes in twins and siblings.
| Traits | Arg462Gln (G>A) diploid genotype | P-value | |||||
|---|---|---|---|---|---|---|---|
| Arg/Arg (G/G) | Gln/Arg (G/A) or Gln/Gln (A/A) | ||||||
| n | Mean | SEM | n | Mean | SEM | ||
| Demographic and Physical | |||||||
| Age, years | 429 | 40.1 | 1.41 | 24 | 38.1 | 2.3 | 3.57E-01 |
| Sex: 1 = M, 2 = F | 110/31 | — | — | 18-Jun | — | — | 9.44E-01 |
| BP status, NT/HTN | 384/45 | — | — | 23/1 | — | — | 3.18E-01 |
| BMI, kg/m2 | 423 | 24.9 | 0.224 | 24 | 26.2 | 1.1 | 1.29E-01 |
| Biochemical | |||||||
| Catecholamines | |||||||
| Urine dopamine, μg/g | 429 | 150.3 | 2.52 | 24 | 208.3 | 10.3 | 3.68E-05 |
| Urine norepinephrine, μg/g | 423 | 28.2 | 0.576 | 23 | 26.5 | 2.13 | 4.40E-01 |
| Urine epinephrine, μg/g | 419 | 10.9 | 0.237 | 24 | 15.7 | 1.21 | 1.06E-03 |
| Plasma dopamine, pg/ml | 401 | 11.4 | 0.017 | 22 | 10.6 | 0.073 | 6.67E-01 |
| Plasma norepinephrine, pg/ml | 403 | 325.5 | 6.99 | 23 | 276.4 | 29.3 | 1.44E-01 |
| Plasma epinephrine, pg/ml | 405 | 21.1 | 0.663 | 23 | 25.9 | 3.32 | 4.16E-01 |
| Renin-angiotensin system | |||||||
| Plasma renin, pg/ml | 340 | 19.6 | 0.831 | 18 | 16.6 | 3.61 | 3.62E-01 |
| Plasma aldosterone, pg/ml | 377 | 134.1 | 3.7 | 19 | 110.5 | 16.3 | 3.28E-01 |
| Inflammation | |||||||
| C reactive protein, ng/ml | 389 | 2.93 | 0.029 | 23 | 3.03 | 0.121 | 3.24E-01 |
| Kidney and urine | |||||||
| Urine albumin excretion, mg/g | 439 | 4.76 | 0.24 | 23 | 6.79 | 1.55 | 3.30E-02 |
| eGFR (MDRD), ml/min | 411 | 94.6 | 1.22 | 22 | 110.5 | 6.81 | 3.20E-02 |
| Urine K+, mEq/g | 425 | 70.3 | 1.5 | 23 | 68.3 | 6.6 | 5.01E-01 |
| Urine Na+, mEq/g | 426 | 129.4 | 3.34 | 23 | 162.9 | 14.3 | 1.20E-02 |
| Urine Cl−, mEq/g | 424 | 149.9 | 3.5 | 23 | 175.1 | 14.9 | 5.49E-01 |
| Urine cortisol, ug/g | 265 | 3.31 | 0.11 | 12 | 2.52 | 0.23 | 6.96E-01 |
| Urine nitric oxide, nmol/g | 412 | 932.8 | 342 | 23 | 1213.5 | 344.9 | 1.46E-01 |
| FELi+, % | 248 | 13.9 | 0.603 | 11 | 23.1 | 3.2 | 8.00E-03 |
| FENa+, % | 372 | 1.79 | 0.127 | 18 | 3.64 | 0.575 | 4.70E-02 |
| Physiological | |||||||
| Hemodynamic | |||||||
| Systolic BP, mmHg | 399 | 123.2 | 0.63 | 21 | 128 | 2.57 | 7.33E-01 |
| Diastolic BP, mmHg | 401 | 75.8 | 0.46 | 21 | 79.1 | 2.11 | 7.05E-01 |
| Heart rate, beats/min | 412 | 69.1 | 0.51 | 23 | 74.5 | 2.17 | 4.76E-01 |
Numbers (n) describe number of individuals analyzed for that genotype and trait. BP indicates blood pressure; NT, normotensive; HTN, hypertensive; CRP, C reactive protein; eGFR, estimated GFR; FELi+, fractional excretion of Li+; FENa+, fractional excretion of Na+; NO, nitric oxide; DBP, diastolic blood pressure; SBP, systolic blood pressure; HR, heart rate; BMI, body mass index. Entries reflect mean ± one SEM. Significant (p < 0.05) differences are indicated in bold type. Descriptive statistics emerged from GEE. Inferential statistics (p-values) emerged from MERLIN, except for FELi+ and FENa+ (from GEE) and urine albumin excretion (by non-parametric Kruskal-Wallis test).