Gait patterns of children and adolescents with Charcot-Marie-Tooth disease.

Gait abnormalities reported in childhood Charcot-Marie-Tooth disease (CMT) include foot-drop, reduced ankle power at push-off and increased knee and hip flexion for swing clearance ('steppage-gait'). The purpose of this study was to describe the gait patterns of 60 children aged 6-17 years with CMT (CMTall ) and distinguish differences based on functional weakness using the CMT Pediatric Scale (CMTPedS). Data were captured using Vicon Nexus system and compared to 50 healthy norms. Data were subdivided into three groups denoting increasing severity of dorsiflexion and plantarflexion weakness from the CMTPedS: no difficulty heel or toe walking (CMTND ), difficulty heel walking (CMTDH ), difficulty toe and heel walking (CMTDTH ). Compared to healthy norms, CMTall demonstrated significantly worse gait profile score, reduced ankle dorsiflexion during swing (foot-drop), reduced ankle dorsiflexor moment in loading response and reduced external thigh-foot angle. Contrary to previous studies there were no signs of reduced ankle power or compensation through 'steppage gait' in this mild-moderately affected population. Instead, CMTall demonstrated reduced internal hip rotation and reduced hip abductor moment. When data were sub-grouped and compared to healthy norms, three different gait patterns at the ankle emerged: CMTND had a near-normal gait pattern, CMTDH presented with foot-drop, and CMTDTH had increased peak dorsiflexion and reduced ankle power generation. Several distinct and abnormal gait patterns were identified in children with CMT, with increasing gait abnormalities in more functionally severe cases. Classifying gait patterns based on disease severity might be a valuable tool in clinical decision making, assessing disease progression and phenotype-genotype correlation studies.