P035 Inflammatory myopathy and metabolic disorders causing myopathies

Abstract Background/Aims Myopathies due to inborn errors of metabolism can be difficult differentiate from inflammatory myopathies. Careful history, examination and laboratory tests are required establish the diagnosis. We present a case Riboflavin Transport Deficiency (Brown-Vialetto-Van Laere syndrome) masquerading as an myopathy. Methods A 37-year-old lady presented with severe proximal muscle weakness. She had background sensory neuropathy chronic anaemia. Notably, her sister history similar symptoms. Creatine Kinase (CK) was 360 IU/L lactate dehydrogenase (LDH) 1700 IU/L. Inflammatory markers were normal. The Ro52 antibody weakly positive. Electromyography showed evidence myopathic features. There symmetrical fatty infiltration atrophy thigh muscles on magnetic resonance imaging (MRI). Positron emission tomography (PET-CT) scan widespread intense uptake in skeletal groups. given 3 pulses IV methyprednisolone followed by oral prednisolone which did not provide clinical benefit. Intravenous immune globulin when she developed bulbar weakness, difficulty swallowing breathing. non-invasive ventilation nasogastric feed. necrotic regenerative fibres biopsy, keeping rhabdomyolysis. Electron microscopy abundant lipid accumulation, suggestive metabolic disorder. Urinary organic acids raised, triggering acylcarnitines blood spot test, increased. This compatible riboflavin transport 'Brown-Vialetto-Van-Laere syndrome'. 500mg TDS started resulting significant improvement. Prednisolone weaned, genetic testing sent, transferred for neurorehabilitation. Results is autosomal recessive neurodegenerative It affects females males equally. Symptoms appear infants well adults. These include hearing visual loss, palsy leading dysphagia speech problems. Paralysis diaphragm may cause breathing difficulty. Initially it then generalized Molecular confirm Patients have abnormal plasma levels flavin or acylcarnitine. Acylcarnitines biological intermediates, used diagnosis acid oxidation disorders. Treatment includes supplementation supportive measures. Response treatment variable. Conclusion initially managed myopathy but respond high dose methylprednisolone. atypical features including normal markers, MRI thighs showing predominantly biopsy accumulation awaiting full results testing. reminder importance tissue reassessing initial if picture changes patients do expected treatment. Disclosure M. Malik: None. A. Mason: B. Davidson: J. Furby: