CD8A and Bailey-Bloch congenital myopathy: AIM, autoimmune myositis; CD8+ T cells, cluster of differentiation 8 positive T cells; DM, dermatomyositis; IBM, inclusion body myositis; MHC, major histocompatibility complex; NAM, necrotizing autoimmune myopathy; OM, overlap myositis; PM, polymyositis