vendex and Ehlers-Danlos-Syndrome

Ehlers-Danlos syndrome (EDS), a connective tissue disorder, may lead to impaired contractile function of lower limb muscles.. To test this hypothesis and to understand the possible mechanisms involved, isometric function of the thigh muscles was investigated at different joint angles (30°, 60°, and 90° of knee flexion) in 7 tenascin-X (TNX)-deficient EDS patients.. There was reduced maximal voluntary torque of the knee extensors (but not knee flexors) across all joint angles in the patients. Time to reach maximal rate of torque development was delayed, and voluntary activation capacity was reduced in patients compared with controls, particularly at 30°.. EDS is associated with muscle weakness, most likely due to increased compliance of the series-elastic component of muscle tissue and failure of maximal voluntary muscle activation. Further research is required to understand the influence of reduced voluntary activation on the severe fatigue reported by EDS patients.

Topics: Adult; Ehlers-Danlos Syndrome; Female; Humans; Knee; Knee Joint; Male; Middle Aged; Motor Activity; Muscle Contraction; Muscle Weakness; Quadriceps Muscle; Thigh; Torque

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.

Topics: Adult; Biopsy; Ehlers-Danlos Syndrome; Electromyography; Female; Humans; Middle Aged; Muscle, Skeletal; Tenascin; Torque; Ultrasonography