Aneurysmal Subarachnoid Hemorrhage in Pediatric DADA2: A Case Report and Literature Review.

Deficiency of adenosine deaminase 2 (DADA2) is a rare autosomal recessive autoinflammatory vasculopathy frequently associated with early-onset central nervous system involvement. Intracranial aneurysm formation and aneurysmal subarachnoid hemorrhage (aSAH) represent uncommon manifestations and remain poorly characterized from a neuroradiological perspective. We report the case of a nine-year-old boy with genetically confirmed DADA2 presenting with aneurysmal subarachnoid hemorrhage who underwent multimodal neurovascular imaging, including digital subtraction angiography (DSA). To contextualize this finding, a structured literature review was performed to identify previously reported cases of intracranial aneurysms in patients with genetically confirmed DADA2. Clinical presentation, hemorrhagic phenotype, aneurysm location, and treatment strategies were analyzed. In addition to our case, seven published patients with genetically confirmed DADA2 and intracranial aneurysms were identified, yielding a total of eight analyzed patients. Hemorrhagic events occurred in five of the eight patients, whereas three of the eight patients presented exclusively with ischemic manifestations. Aneurysms were predominantly multiple and located in the posterior circulation or distal vessels. Anti-TNF-α therapy was administered in seven patients, while aneurysm-directed intervention was reported in one case. These findings suggest that DADA2-associated aneurysms represent a distinct inflammatory neurovascular phenotype characterized by multiplicity and peripheral distribution. In pediatric patients presenting with unexplained aneurysmal subarachnoid hemorrhage, particularly in the context of systemic inflammatory features, DADA2 should be considered as a potential underlying etiology. Comprehensive vascular assessment with DSA may be essential for detecting small or atypically located aneurysms in this setting.