“…Interestingly, none of the risk factors traditionally known to be involved in adult aneurysm formation, such as familiarity, smoking, cocaine use, and arterial hypertension, could be identified with the same frequency among the pediatric population, raising the question of a different pathogenesis. Moreover, pediatric aneurysms show peculiar characteristics, differentiating them from adults: predominant male to female ratio (2:1), high rate of posterior circulation lesions, high proportion of carotid bifurcation location for anterior circulation malformations and remarkable frequency of giant aneurysms (>2.5 cm) [15]. Correlation to congenital disorders (polycystic kidney disease, aortic coarctation, sickle cell anemia, Ehlers-Danlos syndrome, type IV collagenopathy) has also been observed, but it was extremely rare in most of the large series [16].…”