While dystrophin Dp427 provides integrity to the sarcolemma by connecting the extracellular matrix to the intracellular cytoskeleton [7], Dp71 is thought to be involved in the mental retardation present in one third of patients with DMD because Dp71 is the most abundant DMD gene product in adult brain [1], [8], [9], and, more importantly, because patients with mutations located in the Dp71 coding region that significantly affect Dp71 expression exhibited severe mental retardation [10], [11]. The gene discussed is DMD; the disease is Duchenne muscular dystrophy.