Polymorphism in genes encoding endoplasmic reticulum resident aminopeptidases (ERAP1 and ERAP2) predispose to ERA, while genes encoding IL1, IL6, IL10 and MIF increase the risk of sJIA, which itself is considered as a genetically distinct subtype of JIA [16]. The gene discussed is IL1B; the disease is systemic-onset juvenile idiopathic arthritis.