3D Kinematic Gait Analysis in Mucopolysaccharidoses (P4.333)

OBJECTIVE: To identify abnormalities of gait and their correlations with the phenotype severity in patients with mucopolysaccharidoses (MPS) disorders. BACKGROUND: MPS are a group of lysosomal storage disorders caused by specific enzyme deficiencies. Impaired mobility is frequently seen in MPS. The 6-minute walk test, which has been used for MPS clinical trials, measures endurance and is not directly related to variables of gait. A three-dimensional gait analysis of kinematic variables (3D gait kinematics) could be an efficient, non-invasive quantitative method for describing features of gait. Compared to the walk test, it would be more suitable for evaluating MPS and other pediatric populations. DESIGN/METHODS: MPS patients are being recruited from the study entitled, Longitudinal Studies of Brain Structure and Function in MPS Disorders (Lysosomal Disease Network - U54NS065768). The presence of walking difficulties was assessed in 52 MPSI, 17 MPSII and 8 MPSVI subjects. In the initial (and ongoing) recruitment for 3D gait kinematics we are recruiting MPS and normal control subjects. Eight electromagnetic markers, which are secured to the lower limbs and two back regions, transmit signals to four receivers located next to a 6-meter walkway. Angular displacements of the joints, stride length, step width, and velocity along the desired path are computed. RESULTS: Walking difficulties were reported in the MPS subjects: in MPSI 32 out of 52 (62%), in MPSII 8 out of 17 (47%), MPSVI 3 out of 8 (38%). The 3D gait kinematics are being analyzed and statistical tests for differences between MPS and control subjects will be done. CONCLUSIONS: Walking difficulties are present in MPS disorders, with the highest incidence in MPSI, followed by MPSII and then MPSVI. We hypothesize that the 3D gait kinematic analyses will provide quantitative data that describe the impaired gait pattern in MPS and will be sensitive to disease severity. Furthermore, the quantitative analysis has the potential for identifying outcome measures that could be used in future clinical trials. Disclosure: Dr. Nestrasil has nothing to disclose. Dr. Fuller has nothing to disclose. Dr. Ahmed has nothing to disclose. Dr. Shapiro has received personal compensation for activities with Genzyme Corp. Dr. Anderson has nothing to disclose.