Evaluation of motor response in mucopolysaccharidosis patients treated with enzyme replacement therapy

BACKGROUND. The objective of this study is to evaluate the response of the musculoskeletal system to enzyme replacement therapy in a group of patients with Mucopolysaccharidosis (MPS). MATERIAL AND METHODS. A retrospective study was done based on records from 22 patients with different types of MPS (I, II and VI) who were treated with enzyme replacement therapy (ERT). Patient data were evaluated after an average of 21.4 months. Data collected were: Global Motor Function Classification System (GMFCS); measured range of motion (ROM) of the knee, elbow, and shoulder joints; and an evaluation of hand function as proposed by Haddad. A comparison was done between data from the "pre-treatment" and "posttreatment" groups to evaluate the significant clinical differences between the pre and post-treatment periods. RESULTS. In the total group, 13 (59.1%) maintained or improved their motor score and 8 (36.3%) ended up with a worse score. Only ROM of the shoulders saw a statistically significant improvement. The right shoulder increased from 59.7º to 78.4º (p = 0.017), and the left one from 65.2º to 80.2º (p=0,036). CONCLUSIONS. Based on the data, it is possible to conclude that ERT was able to stabilize or improve motor function in the majority of patients and also significantly increase the range of motion of shoulder joints in patients with MPS.