Hereditary pulmonary veno-occlusive disease with a distinctive rare genetic pattern

A 26-year-old man presented with exertional dyspnoea and was diagnosed with pulmonary arterial hypertension (PAH) of uncertain aetiology at multiple hospitals. A high-resolution chest CT scan revealed two key findings: diffuse lobular-centred ground-glass nodules in both lungs and multiple lymph nodes in the hilar and mediastinal regions ( figure 1A,B). Transthoracic echocardiography demonstrated moderate PAH (pulmonary artery systolic pressure 65 mmHg), right ventricular hypertrophy and left ventricular short-axis view with a ‘D’ shape (figure 1C). Right heart acoustic angiography revealed a patent foramen ovale (PFO; figure 1D). Pulmonary function tests showed severely reduced diffusion capacity. Right heart catheterisation confirmed precapillary PAH, with a pulmonary arterial wedge pressure of 13 mm Hg, pulmonary vascular resistance of 6.30 Wood units and cardiac output of 3.49 L/min.