Elevated NT-proBNP levels in systemic AL amyloidosis are a sensitive marker of cardiac involvement, with a cutoff >152 pmol/L being associated with higher mortality rate (72% vs 7.6% per year).61 Abnormal NT-proBNP is predictive of clinically significant cardiac involvement developing in the future.62 BNP/NT-proBNP in general reflects high filling pressures, but amyloid deposits may have a local effect—BNP granules are found in higher quantities in myocytes adjacent to amyloid deposits.63 Increased troponin concentrations are a marker of poor prognosis,64 but the mechanism remains unclear. This evidence concerns the gene NPPB and amyloidosis.