Deficiency of adenosine deaminase 2 (DADA2) presented with bilateral renal subcapsular hematoma: a case report and literature review.

Introduction and importance: Adenosine deaminase 2 (DADA2) deficiency is a monogenic autoinflammatory disease caused by biallelic mutations in the ADA2 gene. Small- and medium-sized vessels may be involved and can cause various clinical symptoms, including features resembling polyarteritis nodosa (PAN). In this article, the authors discuss a unique case of DADA2 disease in which a patient presented with a bilateral renal subcapsular hematoma. Case presentation: An 18-year-old female patient with a history of recurrent optic neuritis presented with a sudden onset of right flank pain as well as nausea, vomiting, weight loss, fever, and elevated arterial blood pressure. Comprehensive abdominal imaging revealed the presence of a bilateral renal subcapsular hematoma. A laboratory test revealed a positive ANA, negative C-ANCA and P-ANCA, and high ESR and CRP. This finding indicated the presence of systemic inflammation. The authors considered DADA2 based on the patient's clinical features and her family's history of autoimmune diseases. A genetic study of the patient revealed the presence of a homozygous ADA2 mutation at chromosomal position 22:17182609, which confirmed the presence of adenosine deaminase 2 deficiency. Clinical discussion: The authors present a rare case of DADA2 disease successfully treated with immunosuppressive therapy. As the authors suspected of having known autoimmune diseases, the patient's clinical and laboratory results improved with corticosteroids and etanercept treatment, leading to notable remission. Under continuous CT imaging, the subcapsular hematoma shrank significantly over two months, decreasing from 8.3 to 5 cm in size for the right-sided hematoma and completely disappearing for the left-sided hematoma. Conclusion: The clinical features of DADA2 may be fatal, but DADA2 may also be curable; therefore, early diagnosis and treatment are essential.