Link Between Abnormal Bleeding and Coagulation Disorders in Noonan Syndromes (PlatNoon)

November 20, 2025 updated by: University Hospital, Bordeaux

Hemorrhagic Risk and Hemostasis Disorders in Noonan Syndrome and Related Conditions

Noonan syndrome is a relatively rare genetic disorder, affecting around 1 in every 1,000 to 2,500 children born. Patients often have a tendency to bleed more easily, particularly from the skin or mucocutaneous tissue (such as mouth or nose). Around half of all the patients are affected by bleedings. The causes of bleeding are variable : some are linked to platelet disorders, others to more complex coagulation problems. However, it is difficult to predict exactly which patients are at risk of severe bleeding, for example during surgery. This is why there are as yet no clear recommendations for preventing this risk before medical intervention. However, it is recommended that patients with Noonan syndrome consult a specialist to assess this risk. Unfortunately, the tests carried out are often unreliable in predicting this significant risk of bleeding. In this study, data from a large group of patients with Noonan syndrome, followed-up in different centers in France, will be studied. During a medical meeting as part of their regular follow-up, a medical doctor assessed their tendency to bleed using a standardized questionnaire (standardized ISTH-BAT score). These results will be compared with the biological tests also performed during their medical follow-up. The aim is to better understand whether these tests are useful in predicting the risk of bleeding. Ultimately, this could help practicians to better anticipate surgical or medical interventions in these patients, and limit bleeding-related risk.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Noonan syndrome (NS) is an autosomal dominant genetic disorder, with an estimated prevalence of 1 in 1,000 to 2,500 births/year. Patients with NS have a cutaneous-mucosal hemorrhagic diathesis, with a prevalence estimated at 46% in a large meta-analysis. The most frequently reported abnormalities are those of primary hemostasis (thrombocytopenia, thrombopathy and Willebrand's disease), as well as those of coagulation, but the correlation between symptomatology and hemostatic disorders is unclear. As a result, there are no specific recommendations in terms of intraoperative hemorrhagic risk prevention, due to a lack of knowledge of the real hemorrhagic risk in these patients, who are particularly exposed to invasive procedures. The PNDS recommends that patients be referred to a haemostasis specialist for assessment of bleeding risk, which entails the performance of investigations that are often not very predictive of bleeding risk. Interpretation of these results with regard to bleeding risk therefore remains unsolved. It is against this backdrop that the aim of this study is to retrospectively collect the bleeding diathesis of a national cohort of patients with SN, using a standardized ISTH-BAT score, performed in the context of a specialized hemostasis consultation by a physician from one of the centers involved in this study. The hemorrhagic diathesis will be compared with the results of the hemostasis exploration performed as part of their follow-up (routine care). This study will make it possible to assess the value of a hemostasis study in predicting the risk of bleeding in these patients.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

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

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patient with noonan syndrome

Description

Inclusion Criteria:

  • All patients with SN, regardless of age
  • Patient/parental guardians informed of the study
  • Patient/legal representative not opposed to the use of their/the child's data
  • Person affiliated or benefiting from a social security scheme

Exclusion Criteria:

- Adults protected by law (guardianship, curatorship or safeguard of justice)

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

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Noonan Syndrome (SN)
Cohort of SN patients meeting study eligibility criteria
Other: Reuse of routine clinical and biological data
Reuse of routine clinical and biological data

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
ISTH-BAT haemorrhagic score
Time Frame: At first clinical visit in the referent center (retrieved retrospectively at inclusion visit)
The ISTH-BAT standardized questionnaire uses 14 items to assess the severity of cutaneous-mucosal, cerebral, articular and per- or post-operative haemorrhagic symptoms
At first clinical visit in the referent center (retrieved retrospectively at inclusion visit)
Willebrand factor
Time Frame: At first clinical visit in the referent center (retrieved retrospectively at inclusion visit)
The Willebrand factor will be obtained from biological tests (in percentage of controls mean value)
At first clinical visit in the referent center (retrieved retrospectively at inclusion visit)
Platelet function
Time Frame: At first clinical visit in the referent center (retrieved retrospectively at inclusion visit)
Platelet function will be obtained from biological tests (in percentage of controls mean value)
At first clinical visit in the referent center (retrieved retrospectively at inclusion visit)

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University Hospital, Bordeaux

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 (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 22, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 20, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 2, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 2, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 20, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CHUBX 2024/96

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

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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