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Genetic and Rare Diseases Information Center (GARD)

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Cystic fibrosis

Other Names for this Disease
  • CF
  • Mucoviscidosis
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Your Question

We have been told that my newborn grandson has been classified as a carrier for cystic fibrosis.  I know that if both parents have the defective gene, the child has a 25 percent chance of actually getting CF, and a 50 percent chance of being a carrier.  My question is, can the child be a carrier if only one parent has the defective gene? 
Thank you.

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

Can the child be a carrier if only one parent has the defective gene? 

Yes. A child who has one parent with a defective (mutated) copy of the CFTR gene has a 50% (1 in 2) chance to also be a carrier. Each person has two copies of each gene and passes along one of those copies to his or her child. Therefore, a carrier of CF can pass either the normal or mutated copy of the gene to each child. If a child’s parent has CF, or two mutated copies of the gene, the child will definitely be a carrier for CF. Because CF is an autosomal recessive condition, carriers typically do not have any signs or symptoms of the condition.

Individuals with specific questions about the genetics of the CFTR gene in their family should speak with a genetics professional.
Last updated: 6/19/2012

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:
Last updated: 10/18/2013