Adult-onset adenosine deaminase-2 deficiency presenting with recurrent juvenile cerebral infarction:A case report

Adenosine deaminase 2 (ADA2) deficiency is a rare autosomal recessive autoinflammatory disorder characterized by systemic vasculitis, recurrent stroke, and immunodeficiency. This results from the biallelic loss-of-function variants of ADA2, leading to enzymatic dysfunction and endothelial impairment. Although it is commonly diagnosed during childhood, adult-onset cases with milder phenotypes have also been reported.

We report a case of adult-onset ADA2 deficiency that presented with recurrent juvenile stroke and systemic vasculitis.

A 42-year-old female with recurrent juvenile stroke and systemic vasculitis symptoms was diagnosed with ADA2 deficiency by genetic testing. The patient had a known pathogenic variant, c.139G>C (p.Gly47Arg), in a homozygous state. Given the mild phenotype and stable condition, the patient continued long-term aspirin therapy without additional immunosuppressive treatment.

This case highlights the importance of considering ADA2 deficiency in patients with unexplained stroke and recurrent vasculitis, particularly those with a history of parental consanguinity. Measurement of serum ADA activity may serve as a potential screening tool for ADA2 deficiency, especially in settings in which genetic testing is not readily available. J. Med. Invest. 72 : 430-433, August, 2025.