CF Twin & Sib Study

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Study Information

The CF Twin/Sib Study team is conducting a nationwide collection of twins and siblings with CF, sponsored by the Cystic Fibrosis Foundation and the National Institutes of Health. We are obtaining a blood sample from twins, siblings, and their parents, and clinical information from the affected twins and siblings. All information collected will be kept confidential and will be used solely for CF research.

This information will be used to determine which patient symptoms may be attributed to the CF (CFTR) gene and which to other possible genes. It will also be used to study the interaction of genes and environment in CF and the effect this has on disease course.

Who is funding this study?

This study is funded by the Cystic Fibrosis Foundation (CFF) and the National Institutes of Health. Johns Hopkins Medicine is the Coordinating Center, and over 100 CF Centers from the US, Australia, and Great Britain are participating in the recruiting efforts. For more information on the National Institues of Health or the CFF, please see our collection of CF-related links.

What do I have to do?

We ask you or your children to give a blood sample, to answer a few questions, and to have information from you or your children's medical records. This means that investigators from Johns Hopkins Medicine will be reviewing your or your children's medical information. The information will include birth history, medication use, current health status, diagnostic information, growth parameters, pulmonary function data, results of laboratory tests and chest X-rays. The duration of your involvement will include time to obtain the blood sample and to answer personal health, family health, and environmental questions and should take approximately 30 to 40 minutes.

Patients are typically enrolled in the study through their physician; however, we are able to accept direct referrals. CF families who are interested in participating in the study are encouraged to contact us.

Why twins?

A twin study provides a powerful method of determining the contribution of genes to a disease trait. It allows us to ask direct questions about genetic control over symptoms of CF and to search for the genes involved. Twins share both environment and genes. Identical (monozygous) twins have the same DNA from each parent and share 100% of their genes. They also share environment before and after birth. The study of identical twins provides insight into environmental effects on disease and the effects of the interaction of genes with the environment.

Like identical twins, fraternal (dizygous) twins share both the womb environment and the family environment after birth. However, they share, on average, only 50% of their genes. By comparing identical twins with fraternal twins, we can determine the contribution of genes( in addition to or interacting with the CF gene )to differences in patient outcome.

Why siblings?

Siblings share on average 50% of their genes and generally share family environment after birth. They help us to further clarify the role of genes and shared environmental factors in the severity of cystic fibrosis. Further, siblings allow us to explore age-related factors. A sib-pair study provides a powerful method of identifying genes contributing to disease. There are far fewer twin pairs with CF than there are sibling pairs, so the addition of sibling pairs enables us to look at symptoms that occur less frequently.

At the completion of the research, we will have more comprehensive knowledge of which CF symptoms are effected by genes and which are influenced more by environment (treatment, diet, etc.). This knowledge will aid CF Researchers and Care Providers in helping to assess risk, and develop/tailor treatments.

Why parents?

Identifying and understanding the differences in transmission of genes from parent to offspring enables us to isolate candidate genes that contribute to the severity of CF disease.

Why your participation is important

Discovering the genetic modifiers of CF will increase our understanding of the mechanisms of the disease and its symptoms. If we were able to have every sibling or twin with CF in this country participate in this study, our ability to detect genetic differences and environmental differences would be very powerful.Once those differences have been identified, we will be better able to care for people with CF.

What happens to my sample?

We are collecting your blood in order to create a permanent source (a bank) of DNA for genetic analysis for each individual. Creating this bank will enable us to research many possible candidate genes without having to draw more blood from patients in order to perform future tests. The blood will be used to extract DNA, the substance in your cells that contains genes, and to establish cell lines A gene is the unit of heredity which is received from each parent that determines a person's characteristics. A cell line is made from white blood cells, which are treated in a way that causes them to grow and allows researchers to create an unlimited supply of DNA on which to conduct tests. This DNA will be used solely for CF research.

This study employs a system for preserving anonymized, code-identified samples of your blood and tissues indefinitely at Johns Hopkins for use in future research for genetic variation in CF. If authorized CF researchers from sites other than Johns Hopkins ask to study factors that contribute to the variability of CF using these samples and your clinical data, they will receive samples and data that have been stripped of any information identifying you.

For more information about the collection and storage of blood samples, please continue.

United States Participants

State	City	Organization Name
AL	Birmingham	University of Alabama at Birmingham
AZ	Phoenix	Phoenix Children's Hospital
CA	Los Angeles	Children's Hospital of Los Angeles
	Oakland	Kaiser Permanente Medical Center
	Orange County	Children's Hospital of Orange County
	Sacramento	Sutter Medical Center
CT	Hartford	Connecticut Children's Medical Center
	New Haven	Yale University SOM
FL	St. Petersburg	All Children's Hospital
IA	Iowa City	University of Iowa Hospitals & Clinics
ID	Boise	St. Luke's CF Clinic
IL	Chicago	University of Chicago Hospitals
		University of Chicago Children's Hospital
		Children's Memorial Hospital & Northwestern University
	Glenview	Children's Asthma Respiratory & Exercise Specialists
IN	Fort Wayne	Lutheran Hospital
KS	Wichita	Via-Christi- St. Francis Campus
MA	Boston	Tufts- New England Medical Center
		Children's Hospital of Boston
	Worcester	University of Massachusetts Memorial Health Care
MD	Baltimore	Johns Hopkins Hospital
MI	Lansing	Michigan State University
MN	Minneapolis	University of Minnesota
		Children's Hospitals and Clinics of Minneapolis
MO	Kansas City	Children's Mercy Hospital and Clinics
	St. Louis	Washington University School of Medicine
MS	Jackson	University of Mississippi Medical Center
NC	Chapel Hill	UNC at Chapel Hill
ND	Bismarck	St. Alexius Heart & Lung CF Clinic
NH	Lebanon	Dartmouth-Hitchcock Medical Center
	Morristown	Morristown Memorial Hospital
NM	Albuquerque	University of New Mexico, SOM
NY	Albany	Albany Medical College
	Rochester	University of Rochester Medical Center, Strong Memorial
	Syracuse	SUNY Upstate Medical University
OH	Akron	Children's Hospital Medical Center of Akron
	Cincinnati	Cincinatti Children's Hospital and Medical Center
	Cleveland	Rainbow Babies and Children's Hospital
	Columbus	Columbus Children's Hospital
	Toledo	Toledo Children's Hospital
OR	Portland	Kaiser Permanente
PA	Philadelphia	Children’s Hospital of Philadelphia
	Pittsburgh	Children's Hospital of Pittsburgh
TN	Memphis	University of Tennessee LeBonheur Children’s Hospital
	Nashville	Vanderbilt University Medical Center
TX	Dallas	St. Paul Medical Center
		Children's Medical Center of Dallas
	Fort Worth	Cook Children's Medical Center
	Houston	Texas Children's Hospital
		Baylor Clinic
	Tyler	University of Texas at Tyler Health Center
UT	Salt Lake City	University of Utah Health Sciences Center
VA	Portsmouth	Naval Medical Center - Portsmouth
	Richmond	Virginia Commonwealth University
VT	Burlington	Fletcher Allen Health Care
WA	Seattle	University of Washington Medical Center
		Children’s Hospital & Regional Medical Center
	Spokane	Providence Medical Center
WI	Green Bay	St. Vincent Hospital
	Marshfield	Marshfield Clinic
	Milwaukee	Children's Hospital of Wisconsin and Froedert Hospital
WV	Morgantown	West Virginia University

International Participants

Country	City	Institution
Australia	Herston, Queensland	Royal Children’s Hospital and the Prince Charles Hospital
Israel	Jerusalem	Hadassah Medical Center
Scotland	Edinburgh	Royal Hospital for Sick Children