Ter Haar NM, et al. - In a large cohort of patients with undefined systemic autoinflammatory diseases (SAIDs), researchers described the clinical features, treatment response and genetic findings. Participants in the study were 187 patients. Arthralgia, myalgia, abdominal pain, fatigue, malaise and mucocutaneous manifestations were most commonly reported symptoms. Compared to patients without genetic variants, those with genetic variants more often had affected relatives. The majority of patients responded well to non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, colchicine and anakinra. With NSAIDs alone, complete remission was rarely accomplished. In patients with distinctive symptoms, notable patterns were found. Overall, the authors concluded that pericarditis and intellectual impairment patients seem to consist of distinct subsets.