Gerrits Karin, Gommans Inge, van Engelen Baziel, de Haan Arnold
Institute for Fundamental and Clinical Human Movement Sciences, Vrije University Amsterdam, 1081 BT Amsterdam, The Netherlands.
Clin Sci (Lond). 2003 Nov;105(5):585-9. doi: 10.1042/CS20030159.
Nemaline myopathy is a congenital neuromuscular disorder, which primarily affects the thin filaments. Clinically the most important feature is muscle weakness; however, this weakness is poorly understood. The present investigation aimed to determine the torque angle relationship of the knee extensor muscles during in vivo muscle contractions in a family with a novel phenotype of nemaline myopathy. The results of this study show that quadriceps weakness occurs predominantly at higher knee flexion angles, but relatively normal strength was found at angles closer to full knee extension. When the relative torque angle relationships were considered, torque loss at smaller than optimum knee flexion angle was greater in the patients compared with the controls. In addition, the optimum angle for maximal quadriceps torque production was shifted towards smaller knee flexion angles in the patients. This suggests that a weakness specifically at higher knee flexion angles probably occurs as a result of adaptations consequently to the disease. Furthermore, it is important to assess muscle function at different joint positions to allow adequate interpretation of muscle weakness.
杆状体肌病是一种先天性神经肌肉疾病，主要影响细肌丝。临床上最重要的特征是肌无力；然而，这种肌无力的情况目前还知之甚少。本研究旨在确定一个具有杆状体肌病新表型的家系在体内肌肉收缩过程中膝伸肌的扭矩-角度关系。该研究结果表明，股四头肌无力主要发生在较高的膝关节屈曲角度，但在接近膝关节完全伸展的角度时肌力相对正常。当考虑相对扭矩-角度关系时，与对照组相比，患者在小于最佳膝关节屈曲角度时的扭矩损失更大。此外，患者产生最大股四头肌扭矩的最佳角度向较小的膝关节屈曲角度偏移。这表明，较高膝关节屈曲角度处的肌无力可能是疾病适应性改变的结果。此外，评估不同关节位置的肌肉功能对于充分解释肌无力情况很重要。
