[Two pairs of brothers with juvenile idiopathic arthritis (JIA): case reports].

This is a case report of juvenile idiopathic arthritis (JIA) in two pairs of brothers followed in the department of pediatric rheumatology, Universidade Federal da Bahia. Genetic involvement in JIA pathogenesis is clear and the risk of recurrence among siblings supports this contribution. An important landmark of this discovery involves the acknowledgment of major histocompatibility complex (MHC) polymorphism contribution to JIA development susceptibility. Despite many advances, the numerous available studies cannot explain several implicit mechanisms in JIA pathogenesis yet.