Reducing Body Myopathy, X-Linked 1b, with Late Childhood or Adult Onset, also known as rbmx1b, is related to reducing body myopathy, x-linked 1a, severe, with infantile or early childhood onset. An important gene associated with Reducing Body Myopathy, X-Linked 1b, with Late Childhood or Adult Onset is FHL1 (Four And A Half LIM Domains 1). Affiliated tissues include skeletal muscle, and related phenotypes are scoliosis and flexion contracture