Genetic Modifiers of Cystic Fibrosis: Sibling Study

This study has been completed.
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI) Identifier:
First received: May 20, 2002
Last updated: April 26, 2012
Last verified: April 2012
The purpose of this study is to identify modifier genes in cystic fibrosis (CF).

Lung Diseases
Cystic Fibrosis

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: Genetic Modifiers of Cystic Fibrosis: Sibling Study

Resource links provided by NLM:

Further study details as provided by National Heart, Lung, and Blood Institute (NHLBI):

Study Start Date: September 2001
Study Completion Date: August 2006
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.


Ages Eligible for Study:   Child, Adult, Senior
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Diagnosis of CF
  Contacts and Locations
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Please refer to this study by its identifier: NCT00037778

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

Publications: Identifier: NCT00037778     History of Changes
Other Study ID Numbers: 1178  R01HL068927 
Study First Received: May 20, 2002
Last Updated: April 26, 2012
Health Authority: United States: Federal Government

Additional relevant MeSH terms:
Cystic Fibrosis
Lung Diseases
Pathologic Processes
Pancreatic Diseases
Digestive System Diseases
Respiratory Tract Diseases
Genetic Diseases, Inborn
Infant, Newborn, Diseases processed this record on August 25, 2016