Magnetic resonance imaging of the anterior compartment of the lower leg is a biomarker for weakness, disability, and impaired gait in childhood Charcot-Marie-Tooth disease.

<bold>Introduction: </bold>Biomarkers of disease severity in Charcot-Marie-Tooth disease (CMT) are required to evaluate early responses to treatment. In this study we used magnetic resonance imaging (MRI) to evaluate the relationship between muscle volume and intramuscular fat accumulation with weakness, disability, and impaired gait in affected children and adolescents.<bold>Methods: </bold>Fifty-five participants underwent MRI of the anterior compartment of the lower leg. Muscle and fat volumes were calculated. Strength was measured using hand-held dynamometry, disability using the CMT Pediatric Scale, and 3-dimensional gait analysis using an 8-camera Vicon Nexus motion capture system.<bold>Results: </bold>Lower muscle volume was significantly associated with reduced dorsiflexion strength, increased disability, impaired gait profile score, and foot drop. Intramuscular fat accumulation was associated with reduced dorsiflexion strength and impaired gait profile score.<bold>Discussion: </bold>The MRI protocol described was feasible, reliable, and sensitive to the magnitude of weakness, disability, and walking difficulties in children with CMT. Muscle Nerve 59:213-217, 2019. [ABSTRACT FROM AUTHOR]