An Observational Prospective Natural History Study of Patients With Mucopolysaccharidosis Type IIIB (MPS IIIB, Sanfilippo Syndrome Type B)

The purpose of this study is to evaluate the natural course of disease progression in Mucopolysaccharidosis Type III (MPS IIIB) patients who are untreated to identify potential surrogate endpoints that may be utilized in future treatment trials of MPS IIIB using predefined assessments including standardized clinical, biochemical, neurocognitive, developmental, and imaging measures.