A case of anti-Ku myositis mimicking limb girdle muscular dystrophy

Anti-Ku is a myositis associated antibody. Histopathology of anti-Ku myositis shows significant muscle fibre necrosis imitating immune mediated necrotising myositis as well as muscular dystrophies. A presentation of isolated proximal muscle weakness with muscle biopsy evidence of muscular dystrophy could mislead the clinician. We present a case of anti-Ku myositis with lower limb predominant weakness, absent extra-muscular manifestations and with an equivocal Anti-Nuclear antibody titre, whose muscle biopsy report came as muscular dystrophy. We would like to highlight the importance of considering anti-Ku myositis as an important differential in biopsies showing significant muscle destruction.