Clinical Variability in Marfan Syndrome

Overview

Marfan syndrome is an autosomal dominant connective tissue disorder caused by mutations in the fibrillin-1 gene (FBN1). Penetrance of FBN1 mutations is complete but intra and inter familial clinical expressivity is extremely variable. The underlying mechanisms for variability are not understood. An interesting mechanism is that the expression level of the wild type and/or mutated allele may play a role in the determination of variability. Principal objective: To evaluate in Marfan patients, if FBN1 expression level (non-mutated or mutated allele) modulates the clinical expression of the disease. Judgment criteria : Correlation allelic expression level-phenotype Perspectives : To search the predictive factors of severity in order to ameliorate precocity of taking care.

Full Title of Study: “Correlations’ Study Between Variability of Expression in FBN1 Gene and Clinical Features in Marfan Patients.”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Non-Randomized
    • Intervention Model: Factorial Assignment
    • Primary Purpose: Basic Science
    • Masking: None (Open Label)
  • Study Primary Completion Date: June 2011

Detailed Description

Marfan syndrome is an autosomal dominant connective tissue disorder caused by mutations in the fibrillin-1 gene (FBN1). Penetrance of FBN1 mutations is complete but intra and inter familial clinical expressivity is extremely variable. The underlying mechanisms for variability are not understood. An interesting mechanism is that the expression level of the wild type and/or mutated allele may play a role in the determination of variability. Principal objective : To evaluate in Marfan patients, if FBN1 expression level (non-mutated or mutated allele) modulates the clinical expression of the disease in individuals from families with clinical variability (intrafamilial) and in independant probands (interfamilial). Judgment criteria : Correlation allelic expression level-phenotype Method : In Marfan patients with a FBN1 nul allele, FBN1 RNA will be extracted from a fibroblast culture. Allelic FBN1 expression level will be performed by quantitative RT-PCR and then compared with clinical evaluation. Number of subjects : 160 subjects, 45 Marfan patients in 15 independent families, 5 patients with the same mutation, 30 with a private mutation leading to a nul allele and 80 non Marfan subjects. Perspectives : To search the predictive factors of severity in order to ameliorate precocity of taking care.

Interventions

  • Procedure: skin punch biopsy and molecular biology
  • Other: fibroblast culture and molecular biology

Arms, Groups and Cohorts

  • Other: Marfan patients
    • Study participants were recruited between 11/2009 and 10/2011, among adult patients consulting in the Multidisciplinary Marfan Clinic of our University Hospital, and having a known mutation in the FBN1 gene. There, patients are evaluated by geneticists, rheumatologists, cardiologists, and ophthalmologists. Systematic slit-lamp examination, cardiac ultrasonography, and radiological investigations are also performed. A skin punch biopsy was used to establish a fibroblast cell culture. We determined mRNA levels for FBN1 and compared it to the clinical involvement.
  • Other: control patients
    • Fibroblasts were obtained from non Marfan patients (cell bank). We determineed mRNA level for FBN1 for each allele.

Clinical Trial Outcome Measures

Primary Measures

  • FBN1 expression level
    • Time Frame: 6 months
    • Evaluation in Marfan patients, of FBN1 expression level (non-mutated or mutated allele) compared to the clinical expression of the disease in idividuals

Participating in This Clinical Trial

Inclusion Criteria

  • Man or woman > 18 years old – With a mutation in FBN1 gene – Has signed an informed consent form Exclusion Criteria:

-No affiliated to a Healthcare System.

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Assistance Publique – Hôpitaux de Paris
  • Collaborator
    • Hospices Civils de Lyon
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Chantal Stheneur, PHD, MD, Principal Investigator, Hôpital Bichat, AP-HP

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