Natural History Studies of Mucopolysaccharidosis III

Mucopolysaccharidosis (MPS) type III (Sanfilippo syndrome) is a group of four devastating
genetic diseases that result in the abnormal accumulation of glycosaminoglycans in body
tissues. In MPSIII the predominant symptoms occur due to accumulation within the central
nervous system (CNS), including the brain and spinal cord, resulting in cognitive decline,
motor dysfunction, and eventual death.

In anticipation for future therapeutic studies for MPSIIIA and MPSIIIB, we are performing a
natural history study to identify the following:

1. Individual rates of decline in motor and cognitive function in a cohort of potential
clinical trial patients

2. The natural history of outcome measures in order to assess their appropriateness as
outcomes in an eventual trial

3. Baseline functional data in patients who will be potential candidates for an eventual
trial

4. Biomarkers of disease progression over a 12-month interval, including changes in brain
MRI and in cerebrospinal fluid

Patients in this study will need to come to Nationwide Children's Hospital in Columbus,
Ohio, three times. At each of these three time points, cognitive outcome measures will be
assessed: at baseline (visit 1), 6 months (visit 2), and at 12 months (visit 3). At baseline
(visit 1) and 12 months (visit 3), an MRI and a lumbar puncture will be performed.

Inclusion Criteria:

1. Age 2 years old or greater

2. Confirmed diagnosis of MPSIIIA or MPSIIIB by either of two methods:

1. No detectable or significantly reduced NAGLU (MPSIIIB) or SGSH (MPSIIIA)
activity in serum or leukocyte assay

2. Genomic DNA mutation analysis demonstrating a homozygous or compound
heterozygous mutations in the NAGLU (MPSIIIB) or SGSH (MPSIIIA) genes

3. Clinical history of or examination features of neurologic dysfunction.

Exclusion Criteria:

1. Inability to participate in the clinical evaluations

2. Presence of a concomitant medical condition that precludes lumbar puncture or use of
anesthetics

3. Inability to be safely sedated in the opinion of the clinical anesthesiologist