When to consider genetic testing for COPA syndrome

Pulmonary features
 Evidence of follicular bronchiolitis or cysts
 Diffuse alveolar haemorrhage
Extrapulmonary features
 Early age of onset (<12 years)
 Family history of disease
 Positive for ANA or ANCA, ±RF

Consider targeted sequencing for exons 8–9 of COPA in patients with one pulmonary feature and two extrapulmonary features, and strongly consider sequencing in patients with one pulmonary and three extrapulmonary features. ANA: anti-nuclear antibody; ANCA: anti-neutrophil cytoplasmic antibody; RF: rheumatoid factor.