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Genetic Modifiers of Cystic Fibrosis: Sibling Study

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00037778
Recruitment Status : Completed
First Posted : May 21, 2002
Last Update Posted : August 31, 2016
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by (Responsible Party):
Johns Hopkins University

Brief Summary:
The purpose of this study is to identify modifier genes in cystic fibrosis (CF).

Condition or disease
Lung Diseases Cystic Fibrosis

Detailed Description:


CF is a highly variable but inevitably fatal single gene disorder. Several lines of evidence suggest that genetic background contributes to the variability of cystic fibrosis phenotypes. The study will develop CF as a model for the identification of modifier genes by capitalizing on the availability of a large motivated population of affected twins and siblings.

The study is in response to a Request for Applications titled "Genetic Modifiers of Single Gene Defect Diseases" released in August 2000 and co-sponsored by the National Institute of Diabetes, Digestive, and Kidney Diseases.


The study has four aims: 1. To identify heritable CF phenotypes by twin study. Intrapair and interpair variance will be determined for selected CF phenotypes, and interclass correlations (monozygotic versus dizygotic) will be performed to identify CF phenotypes with a substantial heritable component. 2. To determine the contribution of genetic and other factors to the variability of CF phenotypes by analysis of affected sibs. Variance component methods will be used to evaluate the CF phenotypes that appear to be heritable based upon other studies or the results of aim 1. 3. To identify biologic phenotypes that correlate with heritable CF phenotypes by clinical study of twins and sibs. Multivariate analysis will be used to find biologic phenotypes associated with CF phenotypes. 4. To identify modifier genes and loci responsible for heritable CF phenotypes by linkage approaches. Identity by descent and transmission disequilibrium methods will be used to test linkage between candidate genes/loci and heritable CF phenotypes. To identify novel loci, genome-wide scans will be performed upon sib pairs selected for extreme concordance or discordance for heritable traits.

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Study Type : Observational
Actual Enrollment : 3459 participants
Observational Model: Family-Based
Time Perspective: Retrospective
Official Title: Genetic Modifiers of Cystic Fibrosis: Sibling Study
Study Start Date : September 2001
Actual Primary Completion Date : February 2013
Actual Study Completion Date : February 2013

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Cystic Fibrosis

Primary Outcome Measures :
  1. Variation among genes in siblings with cystic fibrosis as assessed by DNA [ Time Frame: Single collection ]

Biospecimen Retention:   Samples With DNA
Blood samples

Information from the National Library of Medicine

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Ages Eligible for Study:   up to 100 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population
Siblings with cystic fibrosis

Inclusion Criteria:

  • Diagnosis of CF

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00037778

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United States, Maryland
Johns Hopkins University
Baltimore, Maryland, United States, 21287
Sponsors and Collaborators
Johns Hopkins University
National Heart, Lung, and Blood Institute (NHLBI)
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Principal Investigator: Garry Cutting Johns Hopkins University

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Responsible Party: Johns Hopkins University Identifier: NCT00037778    
Other Study ID Numbers: 1178
R01HL068927 ( U.S. NIH Grant/Contract )
First Posted: May 21, 2002    Key Record Dates
Last Update Posted: August 31, 2016
Last Verified: August 2016
Additional relevant MeSH terms:
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Cystic Fibrosis
Lung Diseases
Pathologic Processes
Pancreatic Diseases
Digestive System Diseases
Respiratory Tract Diseases
Genetic Diseases, Inborn
Infant, Newborn, Diseases