Table 1.

Heritability h² and genetic covariance: Shared genetic and environmental co-determination for traits correlated with urinary dopamine excretion.

Trait	Correlation with uDopamine/creat		Trait heritability (h2)			Rho_E (environmental covariance)			Rho_G (genetic covariance)			n (individuals)
	Spearman Rho	P-value	Estimate	SEM	P-value	Estimate	SEM	P-value	Estimate	SEM	p
Urine catecholamine
uDA/creat	—	—	0.627	0.052	5.96E-16	—	—	—	—	—	—	—
uNE/creat	0.381	1.74E-12	0.490	0.074	1.00E-07	0.264	0.089	4.70E-03	0.612	0.089	6.33E-08	325
uEpi/creat	0.530	2.44E-24	0.781	0.035	2.16E-24	0.548	0.068	1.07E-09	0.541	0.068	1.71E-09	325
Plasma catecholamine
pDA	0.104	6.83E-02	0.565	0.056	1.82E-13	0.294	0.086	1.48E-03	−0.020	0.108	8.52E-01	346
pNE	−0.017	7.62E-01	0.652	0.050	3.19E-16	−0.061	0.092	5.09E-01	0.043	0.105	6.78E-01	355
pEPI	−0.120	3.33E-02	0.665	0.051	5.09E-16	0.068	0.092	4.57E-01	−0.066	0.107	5.40E-01	353
Renal
eGFR (MDRD)	0.166	2.94E-03	0.662	0.049	3.59E-17	0.193	0.088	3.34E-02	0.266	0.098	1.01E-02	347
uAlbumin/creat	0.234	2.35E-05	0.357	0.085	7.56E-05	0.175	0.091	5.93E-02	0.200	0.136	1.54E-01	369
FELi+	0.269	2.02E-05	0.390	0.083	3.06E-05	0.237	0.096	1.88E-02	0.296	0.109	1.12E-02	341
FENa+	0.216	2.08E-04	0.321	0.083	2.29E-04	0.269	0.091	5.32E-03	0.210	0.134	1.38E-01	347

Covariance estimates (±SEM) are from analyses in SOLAR. Heritability, shared genetic determination (genetic covariance, ρ_G also known as pleiotropy) and environmental determination (environmental covariance, ρ_E) for traits correlated with urine DA excretion are indicated. ρ_G and ρ_E are fractions, scaled from −1 to 0, and 0 to +1, as determined in SOLAR. Spearman non-parametric trait-on-trait correlations (Rho) are also reported. MDRD, algorithm for eGFR. Significant differences (p < 0.05) are bold. Analyses were undertaken in MZ and DZ twin pairs of European ancestry.