Sanfilippo Syndrome Type CMPSIIICNCT05825131
Natural History Study of Participants With Sanfilippo Syndrome Type IIIC
An observational study of Sanfilippo Syndrome Type C, run by Phoenix Nest at 2 sites in 2 countries.
Trial summary
This study is planned to document, through retrospective and prospective data collection, syndrome progression in children and young adults with MPS IIIC. Read more about this study
- Who is it for?
- Ages 12 months and older
- Conditions the study is for
- Sanfilippo Syndrome Type C
- How many people
- 30 participants
- Where
- 2 sitesin 2 countries
- Study dates
- 10 Nov 2024to 1 Dec 2028
- How long will I take part?
- 2 Years
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 months and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: Patients with a documented diagnosis of Sanfilippo syndrome type C and who are currently untreated with investigational products (drugs/device) for this disease.
Who may be able to join
- 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
Show all 12Show fewer
- 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.
Who cannot join
- 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
Trial locations and contacts
2 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
2 sites in 2 countries
United States1 site, 1 recruiting
- Recruiting
The University of Texas Southwestern Medical Center
Dallas, Texas, 75390
Alyssa Boudreau Site Coordinator, 214-456-2106, Alyssa.Boudreau@utsouthwestern.edu
Holly Lawrence, Holly.Lawrence@utsouthwestern.edu
About this study
Official title: A Combination Retrospective and Prospective Natural History Study of Participants With Sanfilippo Syndrome Mucopolysaccharidosis Type IIIC (MPS IIIC)
This study is planned to document, through retrospective and prospective data collection, syndrome progression in children and young adults with MPS IIIC.
Read the detailed description
This is a multi-center, natural history study of subjects with Sanfilippo syndrome type C or MPS IIIC. This 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.
At 6-month intervals between clinic visits, participants will be contacted remotely for some safety assessments (e.g., collecting information about concomitant medications, concurrent illnesses, 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 Evidence). The C-RARE app consists of 9 tasks of Activities of Daily Living and socialization as well as three parent reported Sanfilippo specific questionnaires.
The objectives of this study are:
- To enhance the understanding of the natural history and progression of MPS IIIC syndrome on behavior, cognitive abilities, mobility, vision, hearing, speech, and expressive and receptive language
- To define and categorize clinical endpoints that may be used in future clinical trials
- Conditions
- Sanfilippo Syndrome Type C
- Keywords
- Sanfilippo syndrome type C, Mucopolysaccharidosis type III C, MPS IIIC
- Medical subject headings
- Mucopolysaccharidosis III
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| 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. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change From Baseline in Development Quotient (DQ) Using Bayley Scales of Infant Development Assessment Fourth Edition
The Bayley Scales of Infant and Toddler Development, 4th edition (Bayley-4) is a standardized developmental assessment that provides raw scores for 5 subtests (cognitive, expressive communication, receptive communication, fine motor, gross motor) and standard score norms converted to percentiles for 3 scales (cognition, communication, motor). The Bayley-4 raw scores range from 0-162 for the cognitive subtest, 0-84 for the receptive communication subtest, 0-74 for the expressive communication subtest, 0-92 for the fine motor subtest, and 0-116 for the gross motor subtest; a higher score denotes a better outcome. The Bayley-4 standard score norms are converted to percentiles from <0.1 to >99.9 for the cognitive, language, and motor scales; a higher percentile denotes a better outcome.
Measured: Baseline, 12 months and 24 months
Change From Baseline in Vineland Adaptive Behavior Scales Second Edition (VABS-II) Development Quotient (DQ) Score
The VABS-II test measures adaptive behaviors, including the ability to cope with environmental changes, to learn new everyday skills, and to demonstrate independence. The DQ is a means to express a neurodevelopmental/cognitive delay. The DQ was computed as a ratio and expressed as a percentage using the age-equivalent score divided by the age at testing ([age-equivalent score/chronological age] × 100; range, 0, 100). The overall DQ score is calculated from the mean age-equivalent score obtained by averaging out the age-equivalent scores for the all the sub-domains except for Gross and Fine motor skills. This test measures the following 5 key domains: communication, daily living skills, socialization, motor skills, and the adaptive behavior composite (a composite of the other 4 domains). A positive value indicates improvement in health and cognition.
Measured: Baseline, 12 months and 24 months
Secondary outcomes (7)
Change From Baseline on the Color Trail Test Time Score
Children's Color Trail Test (CCTT) assesses sustained attention, sequencing, and other executive functions while reducing reliance on language. A shorter time to completion denotes a better outcome.
Measured: Baseline, 12 months and 24 months
Change From Baseline of Regional Brain Volumes
Assessed by MRI, and especially cortical grey matter volume (CGMV). The brain MRI will assess volumes of the whole brain, basal ganglia, cerebellum, cerebellar gray matter, cerebellar white matter, cerebral white matter, cortical gray matter, cortical white matter, subcortical gray matter and ventricles; corpus callosum, cortical thickness; and whole brain apparent diffusion coefficient.
Measured: Baseline, 12 months and 24 months
Change From Baseline on the Assessment of Behavioral Changes in Sanfilippo (ABCS)
There are 12 questions in the ABCS relating to behavior(s) that caregivers of children with Sanfilippo might find challenging to manage. Change from baseline will be determined by raw scores, a higher score denoting improvement in behavior.
Measured: Baseline, 6 months, 12 months, 18 months, 24 months
Change From Baseline on the Functional Abilities Descriptive Analysis of Type C- Recording Application for Real-world Evidence (C-RARE)
Participants functional abilities will be captured via the C- RARE app at baseline, 6 months, 12 months, 18 months, 24 months while performing tasks of Activities of Daily Living (ADLs). ADLs include: Clothing Management, Eating and Drinking, Chewing and Swallowing, Hygiene, Maintaining and Changing positions, Writing Skills, and Walking.
Measured: Baseline, 6 months, 12 months, 18 months, 24 months
Change From Baseline on the Peabody Picture Vocabulary Test, Fifth Edition
The PPVT-5 is a norm-referenced and individually administered measure of receptive vocabulary. Upon hearing a word, the child will be asked to indicate (by pointing) which picture among four options is specified.
Measured: Baseline, 12 months, 24 months
Change From Baseline on the Expressive Vocabulary Test Third Edition
The EVT-3 is a norm-referenced and individually administered test of expressive language.
Measured: Baseline, 12 months, 24 months
Change From Baseline in Speech Through Picture Description
Picture Description will be used to measure speech rate, utterance length, grammatical competence, lexical retrieval ability, and motor speech features in subjects.
Measured: Baseline, 12 months, 24 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Apr 2023
- Study start10 Nov 2024
- Primary completion30 Jul 2028 (estimated)
- Study completion1 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Sanfilippo Syndrome Type CStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Enrolment
- 30 participants (estimated)
- Target duration
- 2 Years
Sponsor and investigators
- Lead sponsor
- Phoenix Nest
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Vaincres Les Maladies Lysosomales, Association Sanfilippo Sud, Aparito Ltd.
- Responsible party
- Sponsor
- Investigators
- Nathalie Guffon, MD, Principal investigator, Hospices Civils de Lyon
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05825131
- Sponsor's protocol ID
- JLK-447
- Acronym
- MPSIIIC
- Status last verified
- May 2026
- First submitted
- 23 Mar 2023
- Last updated
- 12 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: The data collected as part of the observational study may be analyzed and published. Phoenix Nest recognizes the importance of communicating medical study data and therefore encourages the publication of these data in reputable scientific journals and at seminars or conferences. The details of the processes of producing and reviewing reports, manuscripts, and presentations based on the data from this study will be described in the Clinical Trial Agreement between Phoenix Nest and the Investigator/institution. Consideration for authorship of all publications will be based on compliance with the Uniform Requirements for Manuscripts Submitted to Biomedical Journals ("Uniform Requirements") of the International Committee of Medical Journal Editors (http://www.icmje.org/ethical\_1author.html) and Good Publication Practices.
Study at a glance
From the registry record, last updated by the sponsor on 12 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Combination Retrospective and Prospective Natural History Study of Participants With Sanfilippo Syndrome Mucopolysaccharidosis Type IIIC (MPS IIIC)
- ClinicalTrials.gov ID
- NCT05825131
- Acronym / sponsor ID
- MPSIIIC / JLK-447
- Conditions
- Sanfilippo Syndrome Type C
- Keywords
- Sanfilippo syndrome type C, Mucopolysaccharidosis type III C, MPS IIIC
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Phoenix NestIndustry (pharma, biotech, devices)
- Collaborators
- Vaincres Les Maladies Lysosomales, Association Sanfilippo Sud, Aparito Ltd.
- Study start
- 10 Nov 2024 (actual)
- Primary completion
- 30 Jul 2028 (estimated)
- Study completion
- 1 Dec 2028 (estimated)
- First posted
- 24 Apr 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study is planned to document, through retrospective and prospective data collection, syndrome progression in children and young adults with MPS IIIC.
Detailed description
This is a multi-center, natural history study of subjects with Sanfilippo syndrome type C or MPS IIIC. This 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.
At 6-month intervals between clinic visits, participants will be contacted remotely for some safety assessments (e.g., collecting information about concomitant medications, concurrent illnesses, 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 Evidence). The C-RARE app consists of 9 tasks of Activities of Daily Living and socialization as well as three parent reported Sanfilippo specific questionnaires.
The objectives of this study are:
- To enhance the understanding of the natural history and progression of MPS IIIC syndrome on behavior, cognitive abilities, mobility, vision, hearing, speech, and expressive and receptive language
- To define and categorize clinical endpoints that may be used in future clinical trials
Study design
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Target follow-up
- 2 Years
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| 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. |
Who may qualify
- Ages
- 12 months and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Patients with a documented diagnosis of Sanfilippo syndrome type C and who are currently untreated with investigational products (drugs/device) for this disease.
Key inclusion criteria (12 listed)
- 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
Key exclusion criteria (4 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Change From Baseline in Development Quotient (DQ) Using Bayley Scales of Infant Development Assessment Fourth Edition
Time frame: Baseline, 12 months and 24 months
The Bayley Scales of Infant and Toddler Development, 4th edition (Bayley-4) is a standardized developmental assessment that provides raw scores for 5 subtests (cognitive, expressive communication, receptive communication, fine motor, gross motor) and standard score norms converted to percentiles for 3 scales (cognition, communication, motor). The Bayley-4 raw scores range from 0-162 for the cognitive subtest, 0-84 for the receptive communication subtest, 0-74 for the expressive communication subtest, 0-92 for the fine motor subtest, and 0-116 for the gross motor subtest; a higher score denotes a better outcome. The Bayley-4 standard score norms are converted to percentiles from <0.1 to >99.9 for the cognitive, language, and motor scales; a higher percentile denotes a better outcome.
Change From Baseline in Vineland Adaptive Behavior Scales Second Edition (VABS-II) Development Quotient (DQ) Score
Time frame: Baseline, 12 months and 24 months
The VABS-II test measures adaptive behaviors, including the ability to cope with environmental changes, to learn new everyday skills, and to demonstrate independence. The DQ is a means to express a neurodevelopmental/cognitive delay. The DQ was computed as a ratio and expressed as a percentage using the age-equivalent score divided by the age at testing ([age-equivalent score/chronological age] × 100; range, 0, 100). The overall DQ score is calculated from the mean age-equivalent score obtained by averaging out the age-equivalent scores for the all the sub-domains except for Gross and Fine motor skills. This test measures the following 5 key domains: communication, daily living skills, socialization, motor skills, and the adaptive behavior composite (a composite of the other 4 domains). A positive value indicates improvement in health and cognition.
7 secondary outcomes
Change From Baseline on the Color Trail Test Time Score
Time frame: Baseline, 12 months and 24 months
Change From Baseline of Regional Brain Volumes
Time frame: Baseline, 12 months and 24 months
Change From Baseline on the Assessment of Behavioral Changes in Sanfilippo (ABCS)
Time frame: Baseline, 6 months, 12 months, 18 months, 24 months
Change From Baseline on the Functional Abilities Descriptive Analysis of Type C- Recording Application for Real-world Evidence (C-RARE)
Time frame: Baseline, 6 months, 12 months, 18 months, 24 months
Change From Baseline on the Peabody Picture Vocabulary Test, Fifth Edition
Time frame: Baseline, 12 months, 24 months
Change From Baseline on the Expressive Vocabulary Test Third Edition
Time frame: Baseline, 12 months, 24 months
Change From Baseline in Speech Through Picture Description
Time frame: Baseline, 12 months, 24 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 May 2026.
- Individual participant dataSharing planned: Undecided. The data collected as part of the observational study may be analyzed and published. Phoenix Nest recognizes the importance of communicating medical study data and therefore encourages the publication of these data in reputable scientific journals and at seminars or conferences. The details of the processes of producing and reviewing reports, manuscripts, and presentations based on the data from this study will be described in the Clinical Trial Agreement between Phoenix Nest and the Investigator/institution. Consideration for authorship of all publications will be based on compliance with the Uniform Requirements for Manuscripts Submitted to Biomedical Journals ("Uniform Requirements") of the International Committee of Medical Journal Editors (http://www.icmje.org/ethical_1author.html) and Good Publication Practices.
Related trials for Sanfilippo Syndrome Type C
Active, not recruitingPhase 1
Phase 1 Study of GC1130A in Patients With Sanfilippo Syndrome Type A (MPS IIIA)
Sanfilippo Syndrome Type A
Not yet recruitingObservational study
Natural History to Assess Disease in Patients With MPS IIIC
Sanfilippo Syndrome Type C, Mucopolysaccharidosis (MPS) IIIC
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Nathalie Guffon, MD principal investigator
Hospices Civils de Lyon
2 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Sanfilippo Syndrome Type C, run by Phoenix Nest at 2 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 12 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 12 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States, France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Nathalie Reynes (04 72 12 95 37, nathalie.reynes@chu-lyon.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the 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). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 May 2026; AzTrials last refreshed its copy on 26 Oct 2026.