Amyloidosis and exercise intolerance in ANO5 muscular dystrophy

Anoctamin 5 and dysferlin mutations can result in myopathies with similar clinical phenotype. Amyloid deposits can occur in the muscle of patients with dysferlinopathy. We describe a 53-year-old woman with exercise intolerance since childhood, recurrent rhabdomyolysis and late-onset weakness. Muscle biopsy showed amyloid deposits within the blood vessel walls and around muscle fibers. Mutation analysis identified two pathogenic heterozygous mutations in anoctamin 5 and no mutations in dysferlin. To our knowledge this is the first report of muscle amyloidosis in anoctamin 5 muscular dystrophy. This finding suggests that patients with amyloid in muscle should be screened for anoctamin 5 muscular dystrophy.