Recruiting

Observational Study

Sponsor:

Phoenix Nest

Code:

NCT05825131

Conditions

Sanfilippo Syndrome Type C

Eligibility Criteria

Sex: All

Age: 1+

Healthy Volunteers: Not accepted

Study Details

Brief summary:

This study is planned to document, through retrospective and prospective data collection, syndrome progression in children and young adults with MPS IIIC.

Conditions

Sanfilippo Syndrome Type C

Study ID

NCT05825131

Start date

Nov 10, 2024

Status verified date

May, 2026

Completion date

Dec 1, 2028

Anticipated

Primary completion date

Jul 30, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 1+

Healthy Volunteers: Not accepted

Inclusion 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, pathogenic 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 required
  • 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 patient'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

Study Design

Enrollment

30 participants

Anticipated

Interventions and Outcome Measures

Arms

Retrospective and prospective observational study of patients living with MPS IIIC

Cohort 1: These participants will be a part of the retrospective and prospective Natural History Study, including the C-RARE video assessments. In clinic visits will include: neurocognitive, developmental and behavioral clinical outcome assessments as well as biochemical sample analysis, imaging measures and retrospective medical record review. Participants will record daily living activities through the C-RARE app on their mobile device.

Remote video recording study and retrospective medical chart review of patients living with MPS IIIC

Cohort 2: These participants will not attend in clinic visits. They will be a part of the C-RARE and retrospective medical chart review analysis. 35 patients with a confirmed diagnosis of MPS IIIC from English, Spanish and Portuguese speaking households will be recruited for this portion of the study.

Retrospective medical chart review of MPS IIIC patients either living or deceased

Cohort 3: Deceased or living medical record analysis only of patients with MPS IIIC. Living patients will not be participating in cohort 1 clinical study or cohort 2 C-RARE study.

Primary outcome measure

  • Change From Baseline in Development Quotient (DQ) Using Bayley Scales of Infant Development Assessment Fourth Edition [ Time Frame: Baseline, 12 months and 24 months ]
  • Change From Baseline in Vineland Adaptive Behavior Scales Second Edition (VABS-II) Development Quotient (DQ) Score [ Time Frame: Baseline, 12 months and 24 months ]

Central Contacts and Locations

Central contacts

Nathalie Reynes

04 72 12 95 37nathalie.reynes@chu-lyon.fr

Nathalie Guffon, MD

04 72 12 95 37nathalie.guffon-fouilhoux@chu-lyon.fr

Locations

The University of Texas Southwestern Medical Center

Recruiting

Dallas, Texas, United States, 75390

Contacts

Alyssa Boudreau Site Coordinator

214-456-2106Alyssa.Boudreau@utsouthwestern.edu

Holly Lawrence

Holly.Lawrence@utsouthwestern.edu

Principal Investigator:

Berge Minassian, MD

More Information

Sponsor

Phoenix Nest

Last update posted

May 12, 2026

Last verified

May, 2026

Keywords

  • Sanfilippo syndrome type C
  • Mucopolysaccharidosis type III C
  • MPS IIIC

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Phoenix Nest on 2026-05-12.