The Cognitive Variability in NF1 and TSC Monozygotic Twins

NCT ID: NCT02436746

Last Updated: 2015-05-07

Basic Information

• Recruitment Status: UNKNOWN
• Total Enrollment: 116 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2015-04-30
• Study Completion Date: 2017-04-30

Brief Summary

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.

Conditions

Neurofibromatosis Type I; Tuberous Sclerosis Complex

Study Design

• Observational Model Type: COHORT
• Study Time Perspective: CROSS_SECTIONAL

Study Groups

Neurofibromatosis type I (NF1)

Monozygotic twin pairs with genetically confirmed Neurofibromatosis type I

No interventions assigned to this group

Tuberous Sclerosis Complex (TSC)

Monozygotic twin pairs with genetically confirmed Tuberous Sclerosis Complex

No interventions assigned to this group

Eligibility Criteria

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.

• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Erasmus Medical Center

OTHER

Sponsor Role: lead

Responsible Party

M.C.Y. de Wit, MD PhD

Prof. Y. Elgersma

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Ype Elgersma, Prof.

Role: PRINCIPAL_INVESTIGATOR

Erasmus Medical Center

Locations

Erasmus MC

Rotterdam, , Netherlands

Site Status: RECRUITING

Countries

Netherlands

Central Contacts

Ype Elgersma, Prof.

Role: CONTACT

y.elgersma@erasmusmc.nl

+31 10 7037739

André Rietman, MSc.

Role: CONTACT

a.rietman@erasmusmc.nl

+31 10 7043829

Facility Contacts

Ype Elgersma, Prof.

Role: primary

y.elgersma@erasmusmc.nl

+31 10 7037739

Other Identifiers

MEC-2014-483

Identifier Type: -

Identifier Source: org_study_id