Breakpoint Analysis of de Novo Apparently Balanced Chromosomal Translocations

June 10, 2026 updated by: University Hospital, Montpellier

Development of a Technique to Identify New Genes by Studying and Cloning the Breakpoints of de Novo Apparently Balanced Chromosomal Translocations in Patients Presenting With Syndromic Psychomotor Retardation

For every child with developmental delay, the investigators do a constitutional karyotype. This karyotype can reveal an apparently balanced chromosomal rearrangement (no visible loss or gain of genetic material), such as a translocation between two or more chromosomes of accidental occurrence (not transmitted by parents). However, an apparently balanced translocation does not explain the phenotype of the child. Among the hypotheses that could explain the child's symptoms, there is the possibility of another chromosomal abnormality at the translocation breakpoints, another defect elsewhere on the chromosomes or gene disruption at or near the breakpoints. Because the resolution of a constitutional karyotype is limited, these microanomalies can go undiagnosed. The goal of this study is to look for a microanomaly on a chromosome using a technology of higher resolution than that of the conventional karyotype. The proposed study uses DNA microarray technology on DNA extracted from blood lymphocytes to perform high-resolution analysis of all chromosomes to search for an unbalanced microrearrangement (such as loss or gain of chromosomal material). If no microrearrangement is found, the investigators will pursue by looking for a gene disruption defect at or near the breakpoints involved in the translocation. This will be done by first isolating the chromosomes involved in the translocation by flow cytometry and then hybridizing each of the isolated chromosomes on a new microarray. The purpose of this study is to find a possible cause to explain the phenotype (microrearrangement or gene disruption).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

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Detailed Description

Psychomotor delay is observed in approximately 3% of the general population and has various causes: environmental, genetic (gene or chromosome) or unknown. Chromosomal abnormalities have been identified in 15% of syndromic psychomotor delay (ie. associated with another symptom). Balanced chromosomal translocations are observed in one out of every 1000 individuals and only 6% of patients with de novo apparently balanced translocations have an abnormal phenotype (Warburton, 1991). Review of the literature, concerning the microarray analysis of de novo apparently balanced translocations in patients with psychomotor delay, reveals:* in 40% of cases: an abnormality not identified on the karyotype, either at the translocation breakpoints or at a different location on the genome,* in 60% of cases: no abnormalities are found with a resolution of up to 25kb (Schluth-Bolard et al., 2009). The technique generally used to clone a breakpoint and identify a disrupted gene is a "walk" on the chromosome. This technique uses fluorescent probes, such as BACs or PACs, located on the derivative chromosomes on both sides of the breakpoints. This technique is labor-intensive, time-consuming and expensive because one must probe along the derivative chromosomes, closer and closer to the breakpoint, in order to find the probe overlapping the breakpoint. The investigators propose an original, innovative and quick technique to map chromosome translocation breakpoints in patients with psychomotor delay and no abnormalities on microarray analysis. The main aim is to develop a technique to identify new genes by cloning and mapping chromosome translocation breakpoints. These genes would then be candidate to explain the phenotype of the patient.The study covers a 24 month period and includes 10 patients. The feasibility of the technique, as well as its application to routine laboratory diagnosis, will be evaluated. The study was approved by our local Bioethics Committee and respects french law of bioethics.Methodology:Patients well be selected during staff meetings including clinicians and biologists. An initial microarray analysis well be performed to identify a gain or loss of genetic material. Samples for which no gain or loss is identified well then undergo flow cytometry to isolate the derivative chromosomes. Each derivative chromosome well then be hybridised to a new microarray, thus revealing the breakpoint. The breakpoints will be confirmed by FISH technique and molecular biology techniques well be applied to clone and sequence the breakpoints. Databases well be used to check for genes located in or around the breakpoints. Required information: Administrative data (3 first letters of the last name and 2 first letters of the first name, date of birth, identification of parents, informed consent). Clinical and biological data (phenotype, karyotype, other genetic studies). Expected results: Development of rapid and less expensive technique to clone translocation breakpoints, Identification of genes potentially involved in mental delay and anomalies of embryo development, Evaluation of the distribution of various causes of syndromic mental delay (unbalanced translocation on microarray, additional rearrangement on microarray, gene disruption, or unidentified cause).

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.
Interventional

Enrollment (Actual)

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.
10

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Early Phase 1

Contacts and Locations

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

Study Locations

  • France
      • Montpellier, France, 34295
        • Laboratory of Chromosomal Genetics - Universitary Hospital

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

Description

Inclusion Criteria:

  • patient with syndromic psychomotor delay
  • patient with a apparently balanced de novo chromosomal translocation
  • patient with health insurance
  • informed consent signed by patient or by parents or by the legal representative for children

Exclusion Criteria:

  • patient with an inherited translocation

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: Other
  • Allocation: N/A
  • Interventional Model: Single Group Assignment

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
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.
No Intervention: Psychomotor retardation syndromic
Psychomotor retardation syndromic by Identification of breakpoints
Biological: Identification of breakpoints
Identification of breakpoints in Molecular Biology : demonstration of a chimeric sequence corresponding to a junction region between the two chromosomes

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
Evaluation of the proportion of cases for which a cause explaining the phenotype is found for patients with a apparently balance de novo translocation
Time Frame: 6 months and 2 years
Evaluation of the proportion of cases for which a cause explaining the phenotype is found for patients with a apparently balance de novo translocation
6 months and 2 years

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, Montpellier

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Jacques MD Puechberty, PHD, Laboratory of Chromosomal Genetics - Universitary Hospital

Publications and helpful links

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General Publications

Study record dates

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Study Major Dates

Study Start

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.
October 1, 2011

Primary Completion (Actual)

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 8, 2015

Study Completion (Actual)

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 8, 2015

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).
March 29, 2012

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.
April 3, 2013

First Posted (Estimated)

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.
April 8, 2013

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.
June 12, 2026

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.
June 10, 2026

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.
June 1, 2026

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.
  • 8688

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