Comparison of key distinguishing features between pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with neurofibromatosis type 1 (PH-NF1)
| Idiopathic or heritable PAH | PH-NF1 | |
| Genetics | ||
| Main gene mutation | BMPR2, ACVRL1, ENG, KCNK3, CAV-1, SMAD9 | NF1 |
| Genetic transmission | Autosomal dominant | Autosomal dominant |
| Epidemiology | ||
| Estimated prevalence | 15 cases per million | Prevalence of NF1 is 1 per 3000, prevalence of PH is unknown |
| Sex ratio | Female predominance (∼2:1) | Female predominance (∼4:1) |
| Clinical examination | ||
| Dermatological signs | Absent | Café au lait macules, axillary or groin freckling, subcutaneous neurofibroma |
| Neurological signs | Absent | Possible optic glioma |
| Right heart catheterisation | ||
| mPpa, PAWP, PVR | Increased mPpa, normal PAWP, increased PVR | More severely increased mPpa, normal PAWP, more severely increased PVR |
| Acute vasoreactivity testing | ∼10% in idiopathic PAH (predicts long-term CCB response) | No case reported |
| Pulmonary function | ||
| FEV1, FVC, TLC | Normal (possible mild reduction) | Normal (possible mild reduction) |
| DLCO | Normal (possible mild reduction) | Severe reduction |
| Imaging | ||
| Chest HRCT | Usually normal parenchyma | Ground-glass opacities, lung cysts, lung reticulations |
| V′/Q′ lung scan | Usually normal | Usually normal |
| Treatment | ||
| Targeted PAH therapy | Improved haemodynamics, functional capacity and clinical outcomes | Poor response (based on isolated case reports) |
BMPR2: bone morphogenetic protein receptor type 2; ACVRL1: activin A receptor type II-like kinase 1; ENG: endoglin; KCNK3: potassium channel subfamily K member 3; CAV-1: caveolin 1; mPpa: mean pulmonary artery pressure; PAWP: pulmonary artery wedge pressure; PVR: pulmonary vascular resistance; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; TLC: total lung capacity; DLCO: diffusing capacity of the lung for carbon monoxide; HRCT: high-resolution computed tomography; V′/Q′: ventilation/perfusion; CCB: calcium channel blocker.