Early-onset vasculitis: a toddler with ADA2 deficiency.

Deficiency of adenosine deaminase 2 (DADA2) is an autoinflammatory disease caused by autosomal recessive inherited loss of function mutations in the adenosine deaminase 2 (ADA2) encoding gene, which reduces plasma ADA2 concentration levels.ADA2 has a major role in the maturation and differentiation of the immune system. It ensures immune homeostasis with the help of adenosine receptors on the cell surface because ADA2 acts as an extracellular enzyme that has an important role in regulating extracellular adenosine concentration and mediates cellular immune interactions. We report a fatal outcome of an infant with DADA2 as a result of delayed diagnosis and definitive treatment with bone marrow transplantation.