Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6041592 | Neuromuscular Disorders | 2013 | 6 Pages |
Abstract
Complete deficiency of the extracellular matrix glycoprotein tenascin-X (TNX) leads to recessive forms of Ehlers-Danlos syndrome, clinically characterized by hyperextensible skin, easy bruising and joint hypermobility. Clinical and pathological studies, immunoassay, and molecular analyses were combined to study a patient suffering from progressive muscle weakness. Clinical features included axial and proximal limb muscle weakness, subclinical heart involvement, minimal skin hyperextensibility, no joint abnormalities, and a history of easy bruising. Skeletal muscle biopsy disclosed striking muscle consistency and the abnormal presence of myotendinous junctions in the muscle belly. TNX immunostaining was markedly reduced in muscle and skin, and serum TNX levels were undetectable. Compound heterozygous mutations were identified: a previously reported 30Â kb deletion and a non-synonymous novel missense mutation in the TNXB gene. This study identifies a TNX-deficient patient presenting with a primary muscle disorder, thus expanding the phenotypic spectrum of TNX-related abnormalities. Biopsy findings provide evidence that TNX deficiency leads to muscle softness and to mislocalization of myotendinous junctions.
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Authors
Isabelle Pénisson-Besnier, Valérie Allamand, Philippe Beurrier, Ludovic Martin, Joost Schalkwijk, Ivonne van Vlijmen-Willems, Corine Gartioux, Fransiska Malfait, Delfien Syx, Laurent Macchi, Pascale Marcorelles, Brigitte Arbeille, Anne Croué,