Risk factors for PAH development include specific sociological factors (related to race, gender, and age), clinical features (particularly severe Raynaud’s phenomenon and multiple telangiectasias), cardiological factors (pericarditis and left heart disease), biochemical factors (elevated NT-proBNP and decreased HDL-cholesterol), serological factors (presence of ANA, e.g., anti-U1-RNP or SSA, and antiphospholipid antibodies), and pulmonary factors (interstitial lung disease and decreased DLCO or DLCO/alveolar volume ratio < 70%, FVC/DLCO > 1.6). Here, CALR is linked to pulmonary arterial hypertension.