Natural History Study of Participants With Sanfilippo Syndrome Type IIIC | MPS IIIC | Observational Study | Hospices Civils De Lyon

Page last updated: May 14, 2026

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Study Summary

In this multi-center, natural history study of subjects with Sanfilippo syndrome type C (MPS IIIC), patients will be monitored over a 2-year period to better understand how biomarkers and disease features change over that time period. This study is enrolling at a clinical site in France and one in Texas, USA. There are opportunities to participate at clinical sites, as well as remotely.

The study will combine a retrospective review of medical records and an ongoing collection of clinical data on an observational basis. Real-world data will be collected at home using a recording device. Participants will be asked to attend clinic visits in person on a yearly basis. In clinic visits will include neurocognitive, developmental, behavioral, biochemical, imaging measures as well as retrospective medical record analysis.

Study Title: Natural History Study of Participants With Sanfilippo Syndrome Type IIIC (MPSIIIC)

Trial Listing: Read this clinical trial’s information on ClinicalTrials.gov, for more details including contact information to reach out to the study sites, full inclusion and exclusion criteria. We encourage you to check the Clinicaltrials.gov link frequently for updates on possible new study sites and changes in enroll-ment status or criteria.

Study Opened: November 2024

Study Status: Recruiting

Number of participants: 15 children with MPS IIIC, ages 12 month old and older

Duration: Patients will be studied for 24 months

Participants will be asked to attend clinic visits in person on a yearly basis. In clinic visits will include neu-rocognitive, developmental, behavioral, biochemical, imaging measures as well as retrospective medical record analysis. At 6-month intervals between clinic visits, participants will be contacted remotely for some safety assessments (e.g., collecting information about concomitant medications, concurrent ill-nesses, and procedure-related adverse events [AEs] and serious AEs [SAEs] since last clinic visit). At 6-month intervals, caregivers will complete questionnaires and record home video assessments using a dedicated, compliant study application (app) called C-RARE (Recording Application for Real-World Evi-dence). The C-RARE app consists of 9 tasks of Activities of Daily Living and socialization as well as two parent reported questionnaires.

Locations:

• Hospices Civils De Lyon, Bron, France
• The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America

Qualifications to Participate:

• Inclusion Criteria | To be eligible to participate in the study, patients must meet all of the following criteria:
  • Confirmed diagnosis of Sanfilippo syndrome type C disease by all of the following:
    • Deficiency in heparan-alpha-glucosaminide N-acetyltransferase enzyme activity
    • Has presented with signs/symptoms consistent with Sanfilippo syndrome type C, or, for individuals who have not presented with signs/symptoms of disease (eg, siblings of known patients), the determination of eligibility will be at the discretion of the Sponsor in conjunction with the site Investigator
    • Genomic DNA analysis demonstrating homozygous or compound heterozygous, patho-genic and/or potentially pathogenic variants in the HGSNAT gene
    • Accumulated GAG HS in urine
    • Written informed consent from parent or legal guardian and assent from patient, if re-quired
    • Parent/legal guardian willing to accompany the patient to all study visits
    • Ability to comply with protocol requirements, in the opinion of the Investigator
    • Negative urine pregnancy test at screening (nonsterile females of childbearing potential only).
  • Functional abilities:
    •  Able to take food or liquid by mouth, able to walk with or without assistance.
    • Has an age equivalent on the Vineland Adaptive Behavior Scales (VABS) of ≥1 year.
• Exclusion Criteria | Patients who meet any of the following criteria will not be eligible to participate in the study:
  • Have received an investigational drug within 30 days prior to the Baseline Visit
  • Concomitant illness or medical condition or extenuating circumstance that, in the opinion of the Investigator, might compromise the patient’s ability to comply with protocol requirements, the pa-tient’s well-being or safety, or the interpretability of the patient’s clinical data
  • The presence of significant non-MPS IIIC-related CNS impairment or behavioral disturbances that would confound the scientific rigor or interpretation of results of the study