EIF2AK4 and pulmonary arterial hypertension: European Respiratory Society and European Society of Cardiology (ERS/ESC) guidelines published in 2015 recommended sequential testing starting with bone morphogenetic protein receptor type-2 (BMPR2) sequencing and MLPA in patients with sporadic/familial PAH and EIF2AK4 sequencing in sporadic/familial PVOD/PCH [17], and this approach has been successfully used in many clinical and research settings across the world [80].