[Cap myopathy: a case report].
OBJECTIVE
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.


METHODS
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.
Muñoz-Jareño
N
N
Sección de Neuropatología, Departmento de Anatomía Patológica, Hospital Universitario 12 de Octubre, E-28045 Madrid, Espana. nuriamunozjareno@yahoo.es
López-Martínez
A
A
Martín Fernández-Mayoralas
D
D
Meizoso-Latova
T
T
Cabello
A
A
D000015:Abnormalities, Multiple / Q000235:genetics; D018450:Disease Progression; D005152:Facial Muscles / Q000002:abnormalities; D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000235:genetics; D008297:Male; D018657:Muscle Fibers, Slow-Twitch / Q000201:enzymology / Q000473:pathology*; D009123:Muscle Hypotonia / Q000151:congenital* / Q000473:pathology; D009124:Muscle Proteins / Q000032:analysis; D018482:Muscle, Skeletal / Q000002:abnormalities* / Q000196:embryology / Q000201:enzymology / Q000473:pathology; D009133:Muscular Atrophy / Q000473:pathology; D009210:Myofibrils / Q000648:ultrastructure*; D011782:Quadriplegia / Q000209:etiology; D012131:Respiratory Insufficiency / Q000209:etiology; D012508:Sarcolemma / Q000648:ultrastructure; D013194:Staining and Labeling
D009124:Muscle Proteins