Title:
: Clinical evaluation of COPA syndrome in a European group
Date of publication:
16/6/26
Author:
Roger Brooks
Category:
COPA syndrome
Article body content:
Plain Language
COPA (Coatomer subunit a) syndrome is a very rare inherited immune disorder caused by changes (mutations) in the COPA gene. It causes the immune system to become overactive and attack the body’s own tissues. In this study, doctors from across Europe collected information from 38 people with symptoms of COPA syndrome.
The researchers found that the lungs were affected in almost all patients, often causing inflammation and scarring. Many people also developed arthritis, and some developed kidney disease. The study identified additional problems that had not been well recognised before, including skin, heart, liver and digestive system involvement.
The researchers also found that some people carried a disease-causing COPA mutation but had no symptoms. Most patients showed signs of excessive activation of a pathway called type I interferon signalling, which appears to drive the disease.
Treatment with Janus kinase (JAK inhibitors), medicines that reduce interferon-driven inflammation, showed encouraging results in many patients, helping to stabilise or improve symptoms. The study suggests that earlier recognition and targeted treatment may improve outcomes for people with COPA syndrome.
Why it Matters
This study represents the largest reported cohort of COPA syndrome patients to date, significantly expanding understanding of the disease. It confirms that COPA syndrome is a systemic, disorder with interferon involvement and a broader phenotype than previously recognised.
The findings emphasise that:
- Lung disease is the major driver of morbidity and mortality.
- Kidney disease can be severe and may require transplantation.
- Skin, cardiac, gastrointestinal and hepatic manifestations should be actively screened for.
- Disease can occur without a family history because of de novo mutations or mosaicism.
- Some mutation carriers remain asymptomatic, demonstrating incomplete penetrance.
Hope for the Future
The study provides encouraging evidence that JAK inhibitors can control disease activity in many patients by targeting downstream interferon signalling. These agents are increasingly becoming the preferred targeted treatment approach for COPA syndrome.
The authors also highlight the potential of newer therapies targeting the interferon pathway more directly, particularly:
- Anifrolumab, an interferon alpha and beta receptor subunit 1 (anti-IFNAR1) monoclonal antibody.
- Additional therapies directed at stimulator of interferon genes (STING) and type I interferon signalling.
Improved understanding of disease mechanisms, especially the causes of lung inflammation, may lead to more effective and personalised treatments in the future.
Read More:
Background
COPA syndrome is a rare autosomal dominant monogenic autoinflammatory disease caused by heterozygous mutations in the COPA gene, which encodes the α-subunit of the coatomer protein complex I (COPI). COPI is involved in retrograde transport between the Golgi apparatus and endoplasmic reticulum (ER). Pathogenic COPA variants disrupt retrograde trafficking of STING, leading to chronic STING activation and excessive production of type I interferons and nuclear factor (NF)-κB-mediated inflammatory cytokines.
COPA syndrome shares important clinical and mechanistic overlap with STING-associated vasculopathy with onset in infancy (SAVI) and other type I interferonopathies. Previously recognised core manifestations include:
- Interstitial lung disease (ILD)
- Diffuse alveolar haemorrhage (DAH)
- Inflammatory arthritis
- Glomerular kidney disease
Prior to this study, approximately 70 cases had been reported worldwide, leaving the full clinical spectrum incompletely characterised.
What the Study Found
Cohort Characteristics
- 46 individuals from 29 families carried pathogenic COPA variants.
- 38 individuals were clinically affected, giving a clinical penetrance of 83%.
- Median age of disease onset was 3 years (range: neonatal period–50 years).
- Four patients died during follow-up.
Pulmonary Disease
Pulmonary involvement was the dominant manifestation, occurring in 34/38 patients (89%).
Findings included:
- Interstitial lung disease (31 patients)
- Diffuse alveolar haemorrhage (11 patients overall)
- Pulmonary fibrosis (14 patients)
- Restrictive pulmonary function abnormalities
- Characteristic CT findings including ground-glass opacities and diffuse cystic lung lesions
Several patients required oxygen therapy, ventilatory support, or lung transplantation.
Musculoskeletal Disease
- Joint involvement occurred in 26 patients (68%).
- Polyarthritis was present in 17 patients.
- Four patients developed severe destructive arthritis with deformities and significant disability.
Renal Disease
- Kidney involvement occurred in 7 patients (18%).
- The most common pathology was anti-neutrophil cytoplasmic antibodies (ANCA)-associated pauci-immune glomerulonephritis.
- Two patients required kidney transplantation.
Expansion of the Clinical Phenotype
Previously under-recognised manifestations included:
- Skin disease (12 patients)
- Cardiac involvement (8 patients)
- Gastrointestinal disease (7 patients)
- Liver involvement (5 patients)
Cutaneous findings included chilblains, acral ulcers, purpura, livedo and vasculitic lesions, resembling other type I interferonopathies.
Immunological Findings
- All symptomatic patients tested demonstrated an elevated type I interferon signature.
- Serum IFN-α levels were elevated in all tested patients.
- 97% of tested patients had autoantibodies.
- Common autoantibodies included anti-nuclear antibodies (ANA), ANCA, rheumatoid factor and anti-cyclic citrullinated peptide (CCP) antibodies.
Genetics
- All variants clustered within the WD40 domain of COPA.
- Most mutations were inherited, but:
- 5 were de novo.
- 2 patients had somatic mosaicism.
- No clear genotype–phenotype correlation was identified.
Treatment
- 22 patients received JAK inhibitors (most commonly baricitinib).
- Clinical improvement or stabilisation was reported in 16 of these patients.
- Improvements were particularly noted in lung and joint disease.
- Serious adverse events were uncommon.
Citation David et al., Ann Rheum Dis. 2026; 85(3):547-557.
Authors
David C, Nathan N, Al-Abadi E, Arkwright PD, Bader-Meunier B, Becker S, Belot A, Brennan M, Breton S, Bondet V, Cadranel J, Coulomb l’Hermine A, De Almeida S, Duffy D, Poch TC, de Becdelièvre A, El Khalifi-Boulisfane S, Gattorno M, Gispert-Saüch M, Gothe F, Hatchuel Y, Herdliczko D, Kilinc AA, Koucky V, Labouret G, Manna R, Maillard H, Matoses Ruipérez ML, Matucci-Cerinic C, Mensa-Vilaro A, Michel K, Molina TJ, Lopez Montesinos B, Newman WG, Papenkort J, Rapp C, Rames C, Rice GI, Rose MA, Reumaux H, Sailler L, Schwerk N, Seabra L, Sellam J, Taddio A, Thumerelle C, Tommasini A, Tusseau M, Volpi S, Wetzke M, Weiss L, Welfringer-Morin A, Wislez M, Griese M, Crow YJ, Frémond ML.
Date of publication 25/10/2025