NFKB1 and systemic-onset juvenile idiopathic arthritis: Unsupervised analysis of these platelet pseudobulks found an expanded U7 cluster comprised of 3 patients with active SJIA and 1 patient with MAS, enriched in genes involved in the induction of apoptosis (e.g., NOTCH2 and TNFSF10) and NF-κB signaling (e.g., IRAK1 and TRAF3) (Figure 5, E and F).