Reduced quantitative muscle function in tenascin-X deficient Ehlers-Danlos patients.
The Ehlers-Danlos Syndrome (EDS) is a heterogeneous group of heritable connective tissue disorders. Skeletal muscle features belong to the clinical criteria of EDS and are generally interpreted to result from increased tendon distensibility or exercise avoidance. However, muscle function in EDS has hardly been investigated as such. We performed a pilot study consisting of clinical investigations, electromyography, muscle ultrasound, muscle biopsy, and quantitative muscle function tests on two EDS patients with deficiency of tenascin-X. Quantitative muscle function proved severely reduced despite normal findings on electromyography and muscle biopsy. These findings dispute the interpretation of increased tendon distensibility. We hypothesize that alterations in the extracellular matrix modify myofascial force transmission and thus influence muscle function in EDS.
Voermans
N C
NC
Neuromuscular Centre Nijmegen, Department of Neurology, 935, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands. n.voermans@neuro.umcn.nl
Altenburg
T M
TM
Hamel
B C
BC
de Haan
A
A
van Engelen
B G
BG
D000328:Adult; D001706:Biopsy; D004535:Ehlers-Danlos Syndrome / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D006801:Humans; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D019063:Tenascin / Q000235:genetics*; D019415:Torque; D014463:Ultrasonography
D019063:Tenascin; C081865:tenascin X