For every 50 ng/l increase in NT-proBNP concentration, the odds of carcinoid heart disease increases by 11% (95% confidence interval 5–17%, p<0.0005) and for every 50 ng/ml increase in plasma 5HIAA the odds of carcinoid heart disease increases by 26% (95 confidence interval 14–39%, p<0.0005). The gene discussed is NPPB; the disease is carcinoid heart disease.