Early-onset stroke and vasculopathy associated with mutations in ADA2.

BACKGROUND: We observed a syndrome of intermittent fevers, early-onset lacunar strokes and other neurovascular manifestations, livedoid rash, hepatosplenomegaly, and systemic vasculopathy in three unrelated patients. We suspected a genetic cause because the disorder presented in early childhood. METHODS: We performed whole-exome sequencing in the initial three patients and their unaffected parents and candidate-gene sequencing in three patients with a similar phenotype, as well as two young siblings with polyarteritis nodosa and one patient with small-vessel vasculitis. Enzyme assays, immunoblotting, immunohistochemical testing, flow cytometry, and cytokine profiling were performed on samples from the patients. To study protein function, we used morpholino-mediated knockdowns in zebrafish and short hairpin RNA knockdowns in U937 cells cultured with human dermal endothelial cells. RESULTS: All nine patients carried recessively inherited mutations in CECR1 (cat eye syndrome chromosome region, candidate 1), encoding adenosine deaminase 2 (ADA2), that were predicted to be deleterious; these mutations were rare or absent in healthy controls. Six patients were compound heterozygous for eight CECR1 mutations, whereas the three patients with polyarteritis nodosa or small-vessel vasculitis were homozygous for the p.Gly47Arg mutation. Patients had a marked reduction in the levels of ADA2 and ADA2-specific enzyme activity in the blood. Skin, liver, and brain biopsies revealed vasculopathic changes characterized by compromised endothelial integrity, endothelial cellular activation, and inflammation. Knockdown of a zebrafish ADA2 homologue caused intracranial hemorrhages and neutropenia - phenotypes that were prevented by coinjection with nonmutated (but not with mutated) human CECR1. Monocytes from patients induced damage in cocultured endothelial-cell layers. CONCLUSIONS: Loss-of-function mutations in CECR1 were associated with a spectrum of vascular and inflammatory phenotypes, ranging from early-onset recurrent stroke to systemic vasculopathy or vasculitis. (Funded by the National Institutes of Health Intramural Research Programs and others.).

Biological therapies for the treatment of juvenile idiopathic arthritis: Lessons from the adult and pediatric experiences.

Biologics have advanced the therapy of adult and pediatric arthritis. They have been linked to rare serious adverse outcomes, but the actual risk of these events is controversial in adults, and largely unknown in pediatrics. Because of the paucity of safety and efficacy data in children, pediatric rheumatologists often rely on the adult literature. Herein, we reviewed the adult and pediatric literature on five classes of medicines: Tumor necrosis factor (TNF) inhibitors, anakinra, rituximab, abatacept, and tocilizumab. For efficacy, we reviewed randomized controlled studies in adults, but did include lesser qualities of evidence for pediatrics. For safety, we utilized prospective and retrospective studies, rarely including reports from other inflammatory conditions. The review included studies on rheumatoid arthritis and spondyloarthritis, as well as juvenile idiopathic arthritis. Overall, we found that the TNF inhibitors have generally been found safe and effective in adult and pediatric use, although risks of infections and other adverse events are discussed. Anakinra, rituximab, abatacept, and tocilizumab have also shown positive results in adult trials, but there is minimal pediatric data published with the exception of small studies involving the subgroup of children with systemic onset juvenile idiopathic arthritis, in whom anakinra and tocilizumab may be effective therapies.