Pulmonary hypertension with unclear and/or multifactorial mechanisms
| 5.1 Haematological disorders | Chronic haemolytic anaemia |
| Myeloproliferative disorders | |
| 5.2 Systemic and metabolic disorders | Pulmonary Langerhans cell histiocytosis |
| Gaucher disease | |
| Glycogen storage disease | |
| Neurofibromatosis | |
| Sarcoidosis | |
| 5.3 Others | Chronic renal failure with or without haemodialysis |
| Fibrosing mediastinitis | |
| 5.4 Complex congenital heart disease | See the Task Force article by Rosenzweig et al. [31] in this issue of the European Respiratory Journal |