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Cystic Fibrosis Inheritance: Are you a carrier?

Tue, 12/22/2015 - 15:35 -- IV Solutions

Cystic fibrosis inheritance is passed on through a change in a gene on the 7th chromosome. This change results in the production of the protein CFTR(cystic fibrosis transmembrane regulator). This protein is the reason that the mucus is thick and builds up in people with cystic fibrosis.

Cystic fibrosis inheritance is passed on through autosomal recessive genes, meaning that it is necessary for a child to inherit the changed gene that produces the CFTR protein from BOTH parents in order to express the symptoms of CF.

The prevalence of cystic fibrosis is more pronounced in european communities. 1/25 american caucasians (descendants of european communities) are carriers of the gene that makes the CFTR protein (having one dominant gene and one recessive gene makes you a carrier. Carriers do not express symptoms of cystic fibrosis).

Below, we have illustrated cystic fibrosis inheritance through Punnett squares. These outline the conditions that must be met for a child to inherit cystic fibrosis. The capital “N” represents the dominant gene that doesn’t express cystic fibrosis inheritance.The lower case “n” represents the recessive gene that does express cystic fibrosis inheritance.

NN (No CF, Not a Carrier)

Nn (No CF, But a Carrier)

nn (Has CF)

If both parents are carriers of the CF gene, their children have a 1 in 4 chance of cystic fibrosis inheritance. There’s also a 75% chance of the children having at least one cystic fibrosis gene.

Nn (No CF, But a Carrier)

nn (Has CF)

If one parent is a carrier and the other has cystic fibrosis, the chance of cystic fibrosis inheritance to the child is 50%. There’s also a 100% chance of the child having at least one cystic fibrosis gene.

How the CFTR Gene is Tested For

The CFTR gene provides instructions for making the protein called cystic fibrosis transmembrane conductance regulator. The test to determine if you are a carrier (have one copy of the gene that produces the CFTR protein) takes a simple genetic sample and analyzes it. Since there are over 1,800 mutations of this gene, negative results are not definitive. It is possible to test negative as a CF carrier yes still be a carrier of a CF mutation that does not show up on the test.

Are you a Carrier?

Cystic fibrosis awareness is our strongest tool in progressing our advancements in CF treatment. To determine if you should get tested, you should consider a number of factors. Having a family history of cystic fibrosis inheritance is a risk indicator as well as certain demographics.

  • 1/25 Caucasian-Americans
  • 1/58 Hispanic-Americans
  • 1/61 African-Americans
  • 1/94 Asian-Americans

Check out our blog post, Steps for a Cystic Fibrosis Carrier, to find out more about testing for carriers and how it can affect your family in IV Solutions.

Learn more about Cystic Fibrosis with Us

Cystic Fibrosis Symptoms

The first step towards managing cystic fibrosis is understanding the symptoms. Read more about what the symptoms are, how to manage them, and how to prevent further complications in Cystic Fibrosis Symptoms.

Cystic Fibrosis Treatments

Learn more about the most effective daily cystic fibrosis treatment methods and how you can best manage your symptoms. There are also a few tips to improve your health that go beyond medicines with Cystic Fibrosis Treatments.

Become a part of the IV Solutions CF Family

IV Solutions is more than a pharmacy for cystic fibrosis medications, we’re your personalized CF treatment provider. We build each patient a custom program to help them achieve optimal therapy outcomes.

When it comes to cystic fibrosis medications and treatments, we know that independence means everything. IV Solutions helps you take an active role in CF treatment from the comfort of your home or physician’s office.

With IV Solutions, you’re NEVER ALONE in the fight against cystic fibrosis. We’re here to support you through individualized instruction, proactive refill reminders, on-going care coordination, 1 on 1 counseling, and clinical intervention.

IV Solutions is an active participant and promoter of the CF Community. Visit our facebook page for more resources on cystic fibrosis. If you’re interested in enrolling in an individualized CF care plan, visit our Patients page and contact us today.


Update on Carrier Screening for Cystic Fibrosis. ACOG (American Congress of Obstetricians and Gynecologists). April 2011. Accessed Sept 11, 2015.

FAQ: Carrier Testing for Cystic Fibrosis. UCSF Medical Center. Nov 2, 2010. Accessed Sept 11, 2015.

What does it mean to be a cystic fibrosis carrier? About Health. Dec 10, 2014. Accessed Sept 11, 2015.