A Clinical Case Report of Deficiency of Adenosine Deaminase 2 Syndrome (DADA 2) Presenting as a Brachial Artery Aneurysm.

Introduction: Deficiency of adenosine deaminase 2 (DADA 2) syndrome is a monogenic auto-inflammatory vasculitic syndrome caused by loss of function mutations in the ADA2 gene. Disease manifestations are divided into three major phenotypes: inflammatory/vascular, immune dysregulation, and haematologic, with majority having significant overlap between these phenotypes. The disease has undergone extensive phenotypic expansion since its first description in 2014. It is autosomal recessively inherited and commonly presents with fever, recurrent strokes, livedo racemosa, and polyarteritis nodosa (PAN)-like features. Though the disease has its symptom onset early in childhood, various case series have described patients with symptom onset in adulthood. Visceral arterial aneurysms as a manifestation have been described in literature but not peripheral aneurysms. Here, we describe a young adult with DADA 2 syndrome presenting with peripheral arterial aneurysm involving the brachial artery. Case report: Patient had recurrent episodes of CVA since childhood, a history of orchitis, systemic hypertension, and new onset brachial artery aneurysm at the age of twenty-three. Diagnosis was confirmed by genetic analysis. Tumour necrosis factor inhibitors (TNFi) have emerged as the drug of choice for the treatment of DADA2 and studies revealed a drastic reduction in stroke risk after initiation of TNFi. Based on this experience, we have started the patient on adalimumab, and he is doing well for the past one year. Conclusion: Peripheral artery aneurysm can be a manifestation of vasculitis in DADA 2 syndrome.