Monogenic polyarteritis: the lesson of ADA2 deficiency

Area of Science:

• Genetics and Immunology
• Autoinflammatory Diseases
• Vascular Biology

Background:

• Deficiency of Adenosine Deaminase 2 (DADA2) is an emerging autoinflammatory disorder.
• It presents with early-onset vasculopathy, livedoid rash, systemic and CNS involvement, and mild immunodeficiency.
• DADA2 results from autosomal recessive mutations in the CECR1 gene, encoding ADA2.

Purpose of the Study:

• To summarize the current understanding of DADA2 pathogenesis, clinical manifestations, and treatment.
• To highlight the role of ADA2 in immune homeostasis and vascular integrity.
• To discuss the diagnostic and therapeutic challenges associated with this rare disease.

Main Methods:

• Review of existing literature on DADA2.
• Analysis of genetic mutations in the CECR1 gene.
• Clinical case studies and histopathological findings.

Main Results:

• Nineteen CECR1 mutations identified; pathogenetic mechanisms are under investigation.
• ADA2 deficiency impacts myeloid cells, leading to reduced anti-inflammatory macrophages and increased pro-inflammatory cytokines.
• Clinical spectrum ranges from mild skin manifestations to severe multi-organ disease, often mimicking polyarteritis nodosa.
• CNS involvement is common, with patients experiencing strokes.

Conclusions:

• DADA2 is a complex autoinflammatory disease with significant genetic and clinical heterogeneity.
• Understanding ADA2's role in immunity and endothelium is crucial for targeted therapies.
• Hematopoietic stem cell transplantation shows promise for severe cases, while other treatments remain largely anecdotal.