Cap myopathy: a case report

• Published in: Revista de neurologiá Vol. 45; no. 11; pp. 669 - 671
• Main Authors: Muñoz-Jareño, N, López-Martínez, A, Martín Fernández-Mayoralas, D, Meizoso-Latova, T, Cabello, A
• Format: Journal Article
• Language: Spanish
• Published: Spain 01.12.2007
• Subjects: Abnormalities, Multiple - genetics; Disease Progression; Facial Muscles - abnormalities; Follow-Up Studies; Humans; Infant, Newborn; Intellectual Disability - genetics; Male; Muscle Fibers, Slow-Twitch - enzymology; Muscle Fibers, Slow-Twitch - pathology; Muscle Hypotonia - congenital; Muscle Hypotonia - pathology; Muscle Proteins - analysis; Muscle, Skeletal - abnormalities; Muscle, Skeletal - embryology; Muscle, Skeletal - enzymology; Muscle, Skeletal - pathology; Muscular Atrophy - pathology; Myofibrils - ultrastructure; Quadriplegia - etiology; Respiratory Insufficiency - etiology; Sarcolemma - ultrastructure; Staining and Labeling
• ISSN: 0210-0010
• DOI: 10.33588/rn.4511.2007156

To report a new case of a little-known congenital myopathy. Cap myopathy is a rare congenital disease caused by an alteration in the structure of the fibre, with disorganised myofibrils at the edges. Since it was first described, only a few cases have been reported in the literature. We describe the case of a 16-year-old patient with a history of neonatal hypotonia and psychomotor retardation. At the age of 4 years, the patient presented myopathic facies with atrophied pectoral muscles, winged scapula and lumbar hyperlordosis. A myopathic pattern was observed in the electromyogram. A muscle biopsy showed a very marked predominance of type I fibres, atrophy in part of the population of this type and 20% of them had cap-shaped subsarcolemmal accumulations, which were intensely positive with DPNH and SDH; in the ultrastructural study they correspond to disorganised peripheral myofibrils with preservation of the Z band and the absence of A bands. These alterations are similar to those described in what is known as cap disease or cap myopathy. Today, the patient has mild proximal tetraparesis and moderate restrictive respiratory failure.