Study of L-dopa Treatment in Patients With a Neurodevelopmental Disorder (CTNNB1 Gene) (CTNNB1)

May 21, 2026 updated by: University Hospital, Montpellier

Prospective Pilot Study of L-dopa Treatment in Patients With a Neurodevelopmental Disorder Related to a Pathogenic Variant of the CTNNB1 Gene

Neurodevelopmental disorders (NDD) encompass conditions that impair cognitive and/or emotional development in children, significantly impacting school, social, and family life. They are often linked to genetic causes and, in most cases, lack curative treatment. Among these disorders, monoallelic variations in the CTNNB1 gene cause a rare syndrome known as NEDSDV (Neurodevelopmental disorder with spastic diplegia and visual defects, OMIM: 615075). About twenty patients are reported in France. This syndrome is characterized by global developmental delay, intellectual disability, axial hypotonia, autistic traits, microcephaly, and sometimes ocular anomalies. The clinical profile resembles that of cerebral palsy, and CTNNB1 syndrome is considered a genetic form of this condition, accounting for roughly 4% of cases where a gene has been identified.

Motor impairment is a core feature, with a wide range of movement disorders. Research remains limited, except for a recent publication. Dystonic hypertonia of the lower limbs is frequently described, more pronounced distally than proximally, without pyramidal signs. Spasticity is less common. Gait has been poorly studied: it may be absent or, when acquired, unstable, often tiptoe, and sometimes broad-based, resembling ataxia despite the absence of cerebellar signs. These motor features are difficult to detect before one year of age. To date, no longitudinal studies exist on motor or cognitive progression in CTNNB1 patients; available data are cross-sectional and do not suggest cognitive decline.

From a pathophysiological perspective, the CTNNB1 gene encodes β-catenin, a key protein in cell adhesion and Wnt signaling, involved in cell differentiation and tissue homeostasis. It plays an essential role in embryonic brain development, particularly neuritogenesis and synaptic organization, with a specific impact on dopaminergic structures in the midbrain. Knock-out animal models show severe reduction in dopaminergic neurogenesis. These findings suggest that CTNNB1 anomalies lead to secondary dopaminergic deficits, contributing to clinical signs. The hypothesis is that this deficit could be partially corrected by dopamine supplementation.

Regarding treatment, L-dopa (levodopa), used in dopaminergic disorders, has shown beneficial effects in a CTNNB1 patient. In our neuropediatrics department, two patients treated with L-dopa exhibited notable improvements in alertness, language, and motor skills within two months. These observations support the hypothesis that L-dopa may improve certain motor and non-motor symptoms in these patients.

In summary, CTNNB1 syndrome is a rare form of NDD, clinically similar to cerebral palsy, with complex motor disorders and a probable dopaminergic deficit. Current evidence calls for further research, including longitudinal studies and therapeutic trials targeting the dopaminergic pathway.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

7

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • France
    • Hérault
      • Montpellier, Hérault, France, 34295

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Aged between 1 and 15 years inclusive,
  • Carrier of a pathogenic variant of CTNNB1,
  • Patient with dystonia,
  • Patient willing to comply with the contraception requirements detailed in the protocol.

Exclusion Criteria:

  • Contraindication to treatment with L-dopa and carbidopa or any of its excipients,
  • Current treatment with L-dopa, dopamine agonist, or dopamine blocker,
  • Patients with peptic ulcer disease,
  • Patients with open-angle glaucoma,
  • Patients with orthostatic hypotension,
  • Failure to obtain informed consent signed by both parents or legal guardians and the child's assent, if possible,
  • Patients not affiliated with or not covered by a social security scheme,
  • Individuals participating in another study with an exclusion period still in progress,
  • Individuals who are pregnant or wish to become pregnant within 12 months of inclusion.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Participant
Treatment with L-dopa combined with a peripheral decarboxylase inhibitor (carbidopa) will be introduced gradually over a period of one year from the start of treatment. Motor, cognitive, quality of life and tolerance assessments will be carried out before treatment and at 6 and 12 months.
Drug: L-Dopa
Treatment with L-dopa combined with a peripheral decarboxylase inhibitor (carbidopa) will be introduced gradually over a period of one year from the start of treatment. Motor, cognitive, quality of life and tolerance assessments will be carried out before treatment and at 6 and 12 months.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Assessment of motor skills
Time Frame: Baseline and 6 month follow-up visit
Change in overall motor score using the GMFM-88 scale before treatment (D1) and at 6 months.
Baseline and 6 month follow-up visit

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Assessment of motor skills
Time Frame: 6 month follow-up visit and end-of-study visit at 12 months
Change in motor skills score using the GMFM-88 scale before treatment (D1) and at 12 months, as well as between 6 months and 12 months
6 month follow-up visit and end-of-study visit at 12 months
Assessment of motor skills
Time Frame: Baseline, 6 month follow-up visit and end-of-study visit at 12 months
Changes in the five motor subscores of the five dimensions of the GMFM-88 scale before treatment (D1), at 6 months and 12 months, and between 6 months and 12 months
Baseline, 6 month follow-up visit and end-of-study visit at 12 months
Cognitive assessment
Time Frame: Baseline and end-of-study visit at 12 months
Change in developmental scores (Bayley III) from baseline to 12 months after treatment
Baseline and end-of-study visit at 12 months
Cognitive assessment
Time Frame: Baseline and end-of-study visit at 12 months
Change in cognitive scores (WPPSI or WISC, according to age) from baseline to 12 months after treatment
Baseline and end-of-study visit at 12 months
Cognitve assessment
Time Frame: Baseline and end-of-study visit at 12 months
Change in adaptive behavior scores (Vineland) from baseline to 12 months after treatment
Baseline and end-of-study visit at 12 months
Quality of life assessment
Time Frame: Baseline, 6 month follow-up visit and end-of-study visit at 12 months
Change from baseline to Month 6 and Month 12 in quality of life scores (CP-CHILD)
Baseline, 6 month follow-up visit and end-of-study visit at 12 months
Quality of life assessment
Time Frame: Baseline, 6 month follow-up ans end-of-study visit at 12 months
Change from baseline to Month 6 and Month 12 in Clinical Global Impression of Severity scores (CGI)
Baseline, 6 month follow-up ans end-of-study visit at 12 months
Assessment of tolerance
Time Frame: From baseline to the end-of-study visit at 12 months (continuous assessment throughout the study period)
Number and severity of adverse events from baseline to Month 12
From baseline to the end-of-study visit at 12 months (continuous assessment throughout the study period)
Assessment of tolerance
Time Frame: From baseline to the end-of-study visit at 12 months (continuous assessment throughout the study period)
Changes in clinical status based on neurological and osteoarticular examinations from baseline to Month 12
From baseline to the end-of-study visit at 12 months (continuous assessment throughout the study period)
Assessment of tolerance
Time Frame: From baseline to the end-of-study visit at 12 months (continuous assessment throughout the study period)
Frequency and severity of patient-reported symptoms (diary) from baseline to Month 12
From baseline to the end-of-study visit at 12 months (continuous assessment throughout the study period)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University Hospital, Montpellier

Collaborators

PTC Therapeutics

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 8, 2026

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

May 1, 2027

Study Registration Dates

First Submitted

December 26, 2025

First Submitted That Met QC Criteria

May 21, 2026

First Posted (Actual)

May 29, 2026

Study Record Updates

Last Update Posted (Actual)

May 29, 2026

Last Update Submitted That Met QC Criteria

May 21, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RECMPL23_0426

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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