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CF Source

Genes: An Instruction Manual for the Body

Genes tell our bodies what all of our physical features will look like—height, eye and hair color, the shape of our nose, and so much more. People have 2 copies of most genes. They get one copy from their father and one from their mother.

Sometimes mistakes or defects in genes occur. These are called mutations. Some mutations may keep parts of the body from working as they should. This can result in a person having certain diseases like CF.

The information in the tabs below explain:

  • How family genetics determine if a person may have CF
  • CF gene mutations

If you have any questions, talk to your healthcare provider.

The chances of someone having CF

Every person has 2 copies of every gene. He or she gets 1 copy from each parent.

A person without CF may have:

  • 2 normal copies of the CFTR gene
  • 1 normal copy of the CFTR gene and 1 copy with a mutation. This person is called a "carrier"

A person with CF has disease-causing mutations in both copies of the CFTR gene—1 from each parent.

If both parents are carriers of a disease-causing CFTR gene mutation, there is a 1-in-4 chance that their child will have CF.

Gene Mutation Diagram Key Gene Mutation Family Tree Diagram

Every person, whether he or she has CF or not,
has a gene in the body called the Cystic Fibrosis
Transmembrane Conductance Regulator. This
gene is also known as the CFTR gene or the
CF gene. Mutations in this gene lead to CF.

How many CFTR gene mutations are there?

Scientists have discovered approximately


mutations in the CFTR gene.

Of these, only 127 are known to result in CF.

How many people have CF?


people worldwide and


in the US have CF.

How common are CFTR gene mutations?

The approximate number of people with CF
in the United States who have at least 1
of these mutations:


Of those, about 12,600 have 2 copies
of the F508del mutation.

  • G542X
  • G551D

  • R117H770
  • N1303K670
  • W1282X630

Each of the following CFTR
mutations occur in less than 2% of the people
in the US who have CF:

Gene Mutations


If you don't know what mutations you have or your loved one has, speak with your healthcare provider about taking a test to identify them.