A Novel Mutation c.841C>T in COPA Syndrome of an 11-Year-Old Boy: A Case Report and Short Literature Review

Heterozygous mutations in the C-terminal domain of COPA underlie a complex autoinflammatory syndrome

Mutations in the N-terminal WD40 domain of coatomer protein complex subunit α (COPA) cause a type I interferonopathy, typically characterized by alveolar hemorrhage, arthritis, and nephritis. We described 3 heterozygous mutations in the C-terminal domain (CTD) of COPA (p.C1013S, p.R1058C, and p.R1142X) in 6 children from 3 unrelated families with a similar syndrome of autoinflammation and autoimmunity. We showed that these CTD COPA mutations disrupt the integrity and the function of coat protein complex I (COPI). In COPAR1142X and COPAR1058C fibroblasts, we demonstrated that COPI dysfunction causes both an anterograde ER-to-Golgi and a retrograde Golgi-to-ER trafficking defect. The disturbed intracellular trafficking resulted in a cGAS/STING-dependent upregulation of the type I IFN signaling in patients and patient-derived cell lines, albeit through a distinct molecular mechanism in comparison with mutations in the WD40 domain of COPA. We showed that CTD COPA mutations induce an activation of ER stress and NF-κB signaling in patient-derived primary cell lines. These results demonstrate the importance of the integrity of the CTD of COPA for COPI function and homeostatic intracellular trafficking, essential to ER homeostasis. CTD COPA mutations result in disease by increased ER stress, disturbed intracellular transport, and increased proinflammatory signaling.

COPA syndrome caused by a novel p.Arg227Cys COPA gene variant

BACKGROUND

COPA syndrome is a recently described and rare monogenic autosomal dominant disease caused by heterozygous missense mutations in the Coatomer Protein Subunit alpha (COPA) gene that encodes the alpha subunit of coat protein complex I (COPI). Its main clinical manifestations are inflammatory lung disease, arthritis, and renal disease. The development of inflammation in COPA syndrome maybe due to abnormal autophagic response and abnormal activation of type I interferon pathway. To date, 59 cases of COPA have been reported worldwide.

METHODS

In this case, Trio-whole exome sequencing was employed in the proband and her parents to identify the underlying genetic cause. COPA variant were detected and the clinical presentation of the patient was described.

RESULTS

Herein, we report a case of a 5-year-old girl with COPA syndrome who presented with symptoms of arthritis combined with Anti-neutrophil Cytoplasmic Antibody (ANCA) associated vasculitis (AAV), and progressive renal decline with minimal pulmonary involvement. Trio-whole exome sequencing was performed which revealed a novel heterozygous likely pathogenic variation in the COPA gene (c.679C>T,p.Arg227Cys), which was maternally inherited. Her mother was a heterozygote, but she had no phenotypic manifestations. No other mutations associated with the clinical phenotype were identified.

CONCLUSION

The present identification and characterization of a novel mutation expands the genotypic spectra of the COPA syndrome and provide reference data to guide future clinical diagnosis and treatment of COPA syndrome.

COPA Syndrome from Diagnosis to Treatment: A Clinician's Guide

COPA syndrome is a recently described autosomal dominant inborn error of immunity characterized by high titer autoantibodies and interstitial lung disease, with many individuals also having arthritis and nephritis. Onset is usually in early childhood, with unique disease features including alveolar hemorrhage, which can be insidious, pulmonary cyst formation, and progressive pulmonary fibrosis in nonspecific interstitial pneumonia or lymphocytic interstitial pneumonia patterns. This review explores the clinical presentation, genetics, molecular mechanisms, organ manifestations, and treatment approaches for COPA syndrome, and presents a diagnostic framework of suggested indications for patient testing.

Genome insight and probiotic potential of three novel species of the genus Corynebacterium

Three bacterial strains, B5-R-101^T, TA-R-1^T, and BL-R-1^T, were isolated from the feces of a healthy Korean individual. Cells of these strains were Gram-stain-positive, facultatively anaerobic, oxidase-negative, catalase-positive, rod-shaped, and non-motile. They were able to grow within a temperature range of 10-42°C (optimum, 32-37°C), at a pH range of 2.0-10.0 (optimum, pH 5.5-8.0), and at NaCl concentration of 0.5-10.5% (w/v). All the three strains exhibited 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities ranging from 58 ± 1.62 to 79 ± 1.46% (% inhibition). These strains survived in lower pH (2.0) and in 0.3% bile salt concentration for 4 h. They did not show hemolytic activity and exhibited antimicrobial activity against pathogenic bacteria, such as Escherichia coli, Acinetobacter baumannii, Staphylococcus aureus, and Salmonella enterica. The genomic analysis presented no significant concerns regarding antibiotic resistance or virulence gene content, indicating these strains could be potential probiotic candidates. Phylogenetic analysis showed that they belonged to the genus Corynebacterium, with 98.5-99.0% 16S rRNA gene sequence similarities to other members of the genus. Their major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The abundant cellular fatty acids were C_16:0, C_18:1ω9c, and anteiso-C_19:0. Genomic analysis of these isolates revealed the presence of genes necessary for their survival and growth in the gut environment, such as multi-subunit ATPases, stress response genes, extracellular polymeric substance biosynthesis genes, and antibacterial genes. Furthermore, the genome of each strain possessed biosynthetic gene clusters with antioxidant and antimicrobial potentials, including terpenes, saccharides, polyketides, post-translationally modified peptides (RIPPs), and non-ribosomal peptides (NRPs). In silico DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values were lower than the thresholds to distinguish novel species. Based on phenotypic, genomic, phylogenomic, and phylogenetic analysis, these potential probiotic strains represent novel species within the genus Corynebacterium, for which the names Corynebacterium intestinale sp. nov. (type strain B5-R-101^T = CGMCC 1.19408^T = KCTC 49761^T), Corynebacterium stercoris sp. nov. (type strain TA-R-1^T = CGMCC 1.60014^T = KCTC 49742^T), and Corynebacterium faecium sp. nov. (type strain BL-R-1^T = KCTC 49735^T = TBRC 17331^T) are proposed.

copa-1 mutants experience heightened endoplasmic reticulum stress sensitivity in a C. elegans COPA Syndrome model

COPA Syndrome is a rare, autosomal dominant autoimmune/autoinflammatory disease caused by mutations in COPA , which codes for the alpha subunit of the Coat Protein Complex I (COPI). COPI coated vesicles move proteins in retrograde from the Golgi Apparatus to the Endoplasmic Reticulum. At the cellular level, COPA mutations cause ER stress, though the downstream genetic mechanisms of COPA Syndrome remain undefined. Here, we model COPA Syndrome in Caenorhabditis elegans , using CRISPR/Cas9 to generate patient alleles in copa-1 , the C. elegans COPA ortholog. The two alleles made thus far are superficially wild type under normal growth conditions. However, these animals demonstrate an increased ER stress sensitivity.

Traffic jam within lymphocytes: A clinician's perspective

With the discovery of novel diseases and pathways, as well as a new outlook on certain existing diseases, cellular trafficking disorders attract a great deal of interest and focus. Understanding the function of genes and their products in protein and lipid synthesis, cargo sorting, packaging, and delivery has allowed us to appreciate the intricate pathophysiology of these biological processes at the molecular level and the multi-system disease manifestations of these disorders. This article focuses primarily on lymphocyte intracellular trafficking diseases from a clinician's perspective. Familial hemophagocytic lymphohistiocytosis is the prototypical disease of abnormal vesicular transport in the lymphocytes. In this review, we highlight other mechanisms involved in cellular trafficking, including membrane contact sites, autophagy, and abnormalities of cytoskeletal structures affecting the immune cell function, based on a newer classification system, along with management aspects of these conditions.

Case report: COPA syndrome with interstitial lung disease, skin involvement, and neuromyelitis spectrum disorder

This report describes a case of a 22 months Chinese boy with COPA syndrome bearing the c.715G > C (p.A239P) genotype. In addition to interstitial lung diseae, he also suffered from recurrent chilblain-like rashes, which has not been previously reported, and neuromyelitis optica spectrum disorder (NMOSD), which is a very rare phenotype. Clinical manifestations expanded the phenotype of COPA syndrome. Notably, there is no definitive treatment for COPA syndrome. In this report, the patient has achieved short-term clinical improvement with sirolimus.

A toddler with an unusually severe polyarticular arthritis and a lung involvement: a case report

Background

COPA syndrome is a rare hereditary inflammatory disease caused by mutations in the gene encoding the coatomer protein subunit alpha, causing excessive production of type I interferon.

This case is a reminder for the general paediatrician, highlighting the relevance of the association between arthritis and lung involvement in toddlers.

Case presentation

We report the case of a 2-year-old girl with intermittent limping and joint pain. Her family history was relevant for a Still disease with lung involvement in the mother. Physical examination showed moderate wrist swelling. Laboratory findings on admission showed an increase in inflammatory markers, positive rheumatoid factor, antibodies antinuclear antibody (ANA) and cyclic citrullinated peptide (anti-CCP). Wrists’ ultrasound documented synovial thickening, and chest X-rays showed an unexpected severe interstitial pneumopathy. Genetic testing confirmed the diagnosis of a heterozygous mutation of the COPA gene in c.841C > T (p.R281W). Janus kinase treatment was started (baricitinib, 4 mg daily per os) with a remarkable improvement in limping and joint pain after two weeks.

Conclusions

In cases of recurrent arthritis with family history and multiple involvement organs, a genetic disorder should be suspected and genetic testing should be performed. Furthermore, this case suggests that therapy with jak inhibitors may be effective and safe in interferonopathies.