The Cognitive Variability in NF1 and TSC Monozygotic Twins (COVANTT)

May 4, 2015 updated by: M.C.Y. de Wit, MD PhD, Erasmus Medical Center

The Cognitive Variability in Neurofibromatosis Type I and Tuberous Sclerosis Complex Monozygotic Twins

Both Neurofibromatosis type 1 (NF1) and Tuberous Sclerosis Complex (TSC) are highly heterogeneous diseases. Cognitive features seem to vary widely even between family members carrying the same mutation. This phenotypic variability is not well understood, but is generally assumed to be caused by modifier genes which regulate the affected pathways. However, recent studies brought forward an alternative explanation for the phenotypic variability. Post-mortem studies showed that second hit mutations causing loss of the second ('healthy') allele are more widespread than previously believed. These loss of heterozygosity (LOH) mutations cause bi-allelic loss of the disease-linked gene and are known to cause the gross of somatic features in both diseases (like neurofibromas and hamartomas). Hence, it could be the stochastic occurrence of second-hit mutations in the brain are the cause of the variable cognitive phenotypes.

To investigate to what extent these LOH mutations in the brain contribute to the phenotype and to what extent this variation is due to genetic modifiers factors is unknown. The investigators therefore propose to elucidate this variability by comparing the correlation of cognitive features of monozygotic twins with NF1 or TSC to healthy twins in the population. If modifier genes are the cause of the variability of cognitive features in NF1 and TSC the investigators expect that the variability in cognitive tests in monozygotic twins is the same as monozygotic twins in the healthy population. However, if the variability is caused by the occurrence of LOH mutations, the investigators expect to have a lower correlation in our monozygotic patients compared to the healthy twins.

Study Overview

Status

Status

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

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.

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 (Anticipated)

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.
116

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

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Monozygotic twin pairs with genetically confirmed Neurofibromatosis type I or Tuberous Sclerosis Complex

Description

Inclusion Criteria:

  • The participant is part of a monozygotic twin pair (which is genetically confirmed);
  • NF1 or TSC patients with a genetically confirmed diagnosis;
  • Oral and written informed consent by participant in case ≥ 18 years of age.
  • Oral and written informed consent by both caregivers and assent by participant in case of minor participants.

Exclusion Criteria:

  • A potential subject of whom the twin sibling is not willing or able to participate in this study, will be excluded from participation in this study.
  • Symptomatic brain pathology.

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

  • Observational Models: Cohort
  • Time Perspectives: Cross-Sectional

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.
Neurofibromatosis type I (NF1)
Monozygotic twin pairs with genetically confirmed Neurofibromatosis type I
Tuberous Sclerosis Complex (TSC)
Monozygotic twin pairs with genetically confirmed Tuberous Sclerosis Complex

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
Correlation of full intelligence quotient
Time Frame: 1 day
Depending on age and cognitive development: Bayley Scales of Infant Development (BSID-III) or Wechsler Scale of Intelligence (Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) or Wechsler Intelligence Scale for Children (WISC-III) or Wechsler Adult Intelligence Scale (WAIS-III) )
1 day

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Correlation of word reading ability
Time Frame: 1 day
One-minute word-reading test
1 day
Correlation of attention problems
Time Frame: 1 day
Conners ADHD rating scale
1 day
Correlation of behavioural problems
Time Frame: 1 day
Child Behaviour Checklist or Adult Behaviour Checklist (CBCL/ABCL)
1 day
Correlation of autistic features
Time Frame: 1 day
Social Responsiveness Scale (SRS)
1 day
Correlation of visuospatial judgement (NF1 twins only)
Time Frame: 1 day
Judgement of Line Orientation (JLO)
1 day
Correlation of executive control (TSC twins only)
Time Frame: 1 day
Trail-Making Test parts A & B (TMT)
1 day

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.
Erasmus Medical Center

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: Ype Elgersma, Prof., Erasmus Medical Center

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

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.
April 1, 2015

Primary Completion (Anticipated)

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.
April 1, 2017

Study Completion (Anticipated)

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.
April 1, 2017

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).
April 29, 2015

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.
May 4, 2015

First Posted (Estimate)

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.
May 7, 2015

Study Record Updates

Last Update Posted (Estimate)

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.
May 7, 2015

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.
May 4, 2015

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.
May 1, 2015

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.
  • MEC-2014-483

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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