Natural History to Assess Disease in Patients With MPS IIIC

This is a REMOTE prospective observational study of participants with MPS IIIC. No investigational medicinal product will be administered as part of this study. Patients functional abilities will be captured using video recordings taken by patients legal representative or caregiver using a dedicated clinical video application downloaded from the internet onto a smartphone. The video application is called C-RARE. Electronic observer-reported outcome (ObsRO) questionnaires will be completed by the legal representatives or caregivers via C-RARE. The study will last two years with videos and questionnaires taken every 6 months for a total of 5 time points. Data will then be reviewed and measured for functional change using a scoring scale designed for the use of this study.