Importantly, a ROC curve analysis showed that a plasma GDF-15 cut-off level at 125 pg/ml was able to identify SSc-PAH better than NT-proBNP at 473 pmol/L (93 % sensitivity and 88 % specificity vs 86 % sensitivity and 30 % specificity) and was able to predict mortality in SSc patients [139]. This evidence concerns the gene NPPB and systemic sclerosis.