Explore the vast range of titles available.

The discovery of the genetic cause of an inflammatory disorder shows that, in winnowing down candidate variants obtained by DNA sequencing screens, geneticists have been (so to speak) throwing the baby out with the bath water.

ObjectivesTo analyse the prevalence of CECR1 mutations in patients diagnosed with early onset livedo reticularis and/or haemorrhagic/ischaemic strokes in the context of inflammation or polyarteritis nodosa (PAN). Forty-eight patients from 43 families were included in the study.MethodsDirect sequencing of CECR1 was performed by Sanger analysis. Adenosine deaminase 2 (ADA2) enzymatic activity was analysed in monocyte isolated from patients and healthy controls incubated with adenosine and with or without an ADA1 inhibitor.ResultsBiallelic homozygous or compound heterozygous CECR1 mutations were detected in 15/48 patients. A heterozygous disease-associated mutation (p.G47V) was observed in two affected brothers. The mean age of onset of the genetically positive patients was 24 months (6 months to 7 years). Ten patients displayed one or more cerebral strokes during their disease course. Low immunoglobulin levels were detected in six patients. Thalidomide and anti-TNF (tumour necrosis factor) blockers were the most effective drugs. Patients without CECR1 mutations had a later age at disease onset, a lower prevalence of neurological and skin manifestations; one of these patients displayed all the clinical features of adenosine deaminase 2deficiency (DADA2) and a defective enzymatic activity suggesting the presence of a missed mutation or a synthesis defect.ConclusionsDADA2 accounts for paediatric patients diagnosed with PAN-like disease and strokes and might explain an unrecognised condition in patients followed by adult rheumatologist. Timely diagnosis and treatment with anti-TNF agents are crucial for the prevention of severe complications of the disease. Functional assay to measure ADA2 activity should complement genetic testing in patients with non-confirming genotypes.

Adenosine deaminase 2 (ADA2) is a protein with at least two functions. It is a growth factor affecting leukocytes and endothelial cells and an enzyme that influences purine metabolism. This study shows that mutant ADA2 causes polyarteritis nodosa. Polyarteritis nodosa, first described in 1866, 1 is a systemic necrotizing vasculitis that affects medium and small muscular arteries. 2 , 3 The ensuing tissue ischemia can affect any organ, including the skin, musculoskeletal system, kidneys, gastrointestinal tract, and the cardiovascular and nervous systems. Polyarteritis nodosa is usually diagnosed in middle age or later but can appear in childhood. 2 , 4 , 5 The diagnosis remains challenging despite classification criteria for adults 6 and children, 7 because polyarteritis nodosa frequently presents with nonspecific constitutional symptoms, and organ involvement and disease severity are highly varied. Polyarteritis nodosa is most often primary, but in adults it may be associated . . .

Adenosine deaminase 2 (ADA2) is an enzyme involved in purine metabolism and a growth factor that influences the development of endothelial cells and leukocytes. This study shows that defects in ADA2 cause recurrent fevers, vascular pathologic features, and mild immunodeficiency. Patients with autoinflammatory disease sometimes present with clinical findings that encompass multiple organ systems. 1 Three unrelated children presented to the National Institutes of Health (NIH) Clinical Center with intermittent fevers, recurrent lacunar strokes, elevated levels of acute-phase reactants, livedoid rash, hepatosplenomegaly, and hypogammaglobulinemia. Collectively, these findings do not easily fit with any of the known inherited autoinflammatory diseases. Hereditary or acquired vascular disorders can have protean manifestations yet be caused by mutations in a single gene. Diseases such as the Aicardi–Goutières syndrome, 2 , 3 polypoidal choroidal vasculopathy, 4 sickle cell anemia, 5 livedoid vasculopathy, 6 and the small-vessel vasculitides 7 , 8 are examples of systemic . . .

BackgroundVEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a newly discovered autoinflammatory condition characterised by somatic mutation of the UBA1 gene. The syndrome leads to multi-system inflammation affecting predominantly the skin, lungs and bone marrow.MethodsWe undertook a systematic review of the multisystem features and genotypes observed in VEXAS syndrome. Articles discussing VEXAS syndrome were included. Medline, Embase and Cochrane databases were searched.Information was extracted on: demographics, type and prevalence of clinical manifestations, genetic mutations and treatment. Meta-analysis using a random effects model was used to determine pooled estimates of serum markers.ResultsFrom 303 articles, 90 were included, comprising 394 patients with VEXAS. 99.2% were male, with a mean age of 67.1 years (SD 8.5) at disease onset.The most frequent diagnoses made prior to VEXAS were: relapsing polychondritis (n = 59); Sweet’s syndrome (n = 24); polyarteritis nodosa (n = 11); and myelodysplastic syndrome (n = 10). Fever was reported in 270 cases (68.5%) and weight loss in 79 (20.1%). Most patients had haematological (n = 342; 86.8%), dermatological (n = 321; 81.5%), pulmonary (n = 297; 75.4%%) and musculoskeletal (n = 172; 43.7%) involvement, although other organ manifestations of varying prevalence were also recorded.The most commonly reported mutations were “c.122T > C pMET41Thr” (n = 124), “c.121A > G pMET41Val” (n = 62) and “c.121A > C pMet41Leu” (n = 52).Most patients received glucocorticoids (n = 240; 60.9%) followed by methotrexate (n = 82; 20.8%) and IL-6 inhibitors (n = 61, 15.4%). One patient underwent splenectomy; 24 received bone marrow transplants.ConclusionVEXAS syndrome is a rare disorder affecting predominantly middle-aged men. This is the first systematic review to capture clinical manifestations, genetics and treatment of reported cases. Further studies are needed to optimise treatment and subsequently reduce morbidity and mortality.

Background Loss-of-function CECR1 mutations cause polyarteritis nodosa (PAN) with childhood onset, an autoinflammatory disorder without significant signs of autoimmunity. Herein we describe the unusual presentation of an autoimmune phenotype with constitutive type I interferon activation in siblings with adenosine deaminase 2 (ADA2) deficiency. Case presentation We describe two siblings with early-onset recurrent strokes, arthritis, oral ulcers, discoid rash, peripheral vascular occlusive disease and high antinuclear antibody titers. Assessment of interferon signatures in blood revealed constitutive type I interferon activation. Aicardi-Goutières syndrome (AGS) was suspected, but no mutation in the known AGS genes were detected. Whole exome sequencing identified compound heterozygosity for a known and a novel mutation in the CECR1 gene. Functional consequences of the mutations were demonstrated by marked reduction in ADA2 catalytic activity. Conclusions Our findings demonstrate that ADA2 deficiency can cause an unusual autoimmune phenotype extending the phenotypic spectrum of PAN. Constitutive interferon I activation in patient blood suggests a possible role of type I interferon in disease pathogenesis which may have therapeutic implications.

Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive disease resulting from loss-of-function pathogenic variants in ADA2 gene, which might resemble polyarteritis nodosa (PAN). The authors present two pediatric cases of ADA2 deficiency with phenotypic manifestations of PAN, including an unusual presentation with spinal cord ischemia. Also described is an assessment of ADA2 activity and gene expression profiling with description of a previously unreported homozygous variant, c.1226C > A (p.(Pro409His)), detected in a patient with consanguineous parents, confirmed by near-absent ADA2 plasma enzymatic activity. The authors suggest to first obtain enzymatic activity, whenever DADA2 is suspected, before proceeding to genetic testing, due to its excellent cost-effective results. Moreover, physicians must be aware of this monogenic disorder, especially in the case of early-onset PAN-like manifestations, having a family member with similar manifestations or having consanguineous parents suggesting an autosomal recessive inheritance pattern. Given the multi-organ involvement, recognizing the diverse manifestations is a crucial step towards timely diagnosis and management of this potentially fatal but often treatable syndrome.

To the Editor: Zhou et al. 1 and Navon Elkan et al. 2 (both in the March 6 issue) speculate that hematopoietic stem-cell transplantation (HSCT) or enzyme-replacement therapy may be beneficial in patients with adenosine deaminase 2 (ADA2) deficiency. We report the clinical course of two brothers with recently diagnosed ADA2 deficiency resulting from a homozygous mutation in CECR1 (p.R169Q). One sibling underwent HSCT in 2003. ( CECR1 encodes the protein ADA2.) One brother presented in 1999, at 6 months of age, with livedo reticularis, hepatosplenomegaly, hypercoagulability, granulocytopenia, and complete red-cell aplasia. He underwent HSCT in 2003 for a presumed diagnosis of . . .

Adenosine deaminase 2 (ADA2) deficiency due to CECR1 mutations is a recently defined disorder that involves systemic inflammation and vasculopathy often associated with polyarteritis nodosa. We report on a 5-year-old girl with a severe vasculopathy who carried two novel mutations in CECR1. Conclusion : Identification of CECR1 mutations in patients with vasculopathy may lead to earlier diagnosis of ADA2 deficiency.