MRAP and enthesitis-related juvenile idiopathic arthritis: Enthesitis Related Arthritis (ERA) is a subtype of Juvenile Idiopathic Arthritis (JIA) with unique characteristics, including male predominance with later onset, Human Leukocyte Antigen (HLA)-B27 association as well as enthesitis and axial skeleton in addition to peripheral joint involvements, which differentiates it from other JIA categories.