IntroductionMultiple-acyl-CoA dehydrogenase deficiency or MADD is a rare autosomal recessive disorder caused by deficiency of electron transfer flavoprotein. Late onset form of MADD typically present with slowly progressive proximal weakness, myalgia, lethargy, vomiting, hypoglycaemia and metabolic acidosis. This condition is highly variable in age and symptoms at onset. The mean delay between onset of symptoms and diagnosis was 3.9 years. Confirmation of the diagnosis requires relatively complicated tests including muscle biopsy, Acylcarnitine profiling, urinary organic acid analysis and molecular gene testing. MADD responds dramatically to riboflavin supplementation and dietary treatment i.e. high carbohydrate, low fat and low protein diet. We report of a case of Multiple-Acyl-CoA Dehydrogenase Deficiency (MADD) and a review of the literature.CaseA 22 year old female presented with 3 year history of slowly progressive muscle weakness, fatigue and dyspnea on minimal exertion. Clinical examination revealed profound neck extension weakness (‘dropped head syndrome’), proximal muscle weakness (winged scapula and positive Gower’s sign), mild dysphagia and dysarthria. There was no obvious facial weakness, ptosis or ophthalmoplegia. Muscle biopsy showed prominent lipid and generalised hypotrophy of type I fibres. The diagnosis of MADD was suspected on the basis of clinical presentation. The patient was commenced on riboflavin, carnitine supplementation and low protein, low fat diet. Her symptoms improved significantly over 2 months (improvement in muscle strength and respiratory function, FVC improved from 42% to 89%). Acylcarnitine and amino acid screen results came back later showing elevated levels of C6, C8, C10 and C12 in keeping with the diagnosis of MADD.ConclusionMultiple-acyl-CoA dehydrogenase deficiency is a rare genetic metabolic myopathy. It is under-recognised and diagnosis of the adult onset form is often challenging. The majority of patients respond well to riboflavin and dietary modifications with excellent clinical outcome.References. Sharp LJ, Haller RG. Metabolic and mitochondrial myopathies. Neurol Clin2014Aug;32:777–99.. Grunert SC. Clinical and genetical heterogeneity of late-onset multiple acyl-coenzyme: A dehydrogenase deficiency. Orphanet J Rare Dis2014Jul 22;9:117.. Angelini C. Spectrum of metabolic myopathies. Biochem Biophys Acta2015Apr;1852(4):615–21.. Yee WC. Two eminently treatable genetic metabolic myopathies. Neurol India2008Jul–Sep;56(3):333–8.
Late-onset multiple acyl-CoA dehydrogenase deficiency mimicking myositis in an elderly patient: a case report
