If your child has cystic fibrosis (CF), then their genes play a role in their condition. The specific genes that cause their CF will also affect the types of medication that may work for them. That’s why it’s so important to understand the part genes play in CF when making decisions about your child’s healthcare.

How do genetic mutations cause CF?

CF is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. This gene is responsible for producing CFTR proteins. When these proteins are working properly, they help regulate the flow of fluids and salt into and out of cells.

According to the Cystic Fibrosis Foundation (CFF), scientists have identified more than 1,700 different types of mutations in the gene that can cause CF. To develop CF, your child must inherit two mutated copies of the CFTR gene — one from each biological parent.

Depending on the specific type of genetic mutations that your child has, they might be unable to produce CFTR proteins. In other cases, they might produce CFTR proteins that don’t work properly. These defects cause mucus to build up in their lungs and puts them at risk of complications.

What types of mutations can cause CF?

Scientists have developed different ways to classify mutations in the CFTR gene. They currently sort CFTR gene mutations into five groups, based on the problems they can cause:

  • Class 1: protein production mutations
  • Class 2: protein processing mutations
  • Class 3: gating mutations
  • Class 4: conduction mutations
  • Class 5: insufficient protein mutations

The specific types of genetic mutations that your child has can influence the symptoms they develop. It can also affect their treatment options.

How do genetic mutations affect treatment options?

In recent years, researchers have started to match different types of medication to different types of mutations in the CFTR gene. This process is known as theratyping. It can potentially help your child’s doctor determine which treatment plan is best for them.

Depending on your child’s age and genetics, their doctor might prescribe a CFTR modulator. This class of medication can be used to treat some people with CF. Specific types of CFTR modulators only work for people with specific types of CFTR gene mutations.

So far, the U.S. Food and Drug Administration (FDA) has approved three CFTR modulator therapies:

  • ivacaftor (Kalydeco)
  • lumacaftor/ivacaftor (Orkambi)
  • tezacaftor/ivacaftor (Symdeko)

About 60 percent of people with CF could benefit from one of these drugs, reports the CFF. In the future, scientists hope to develop other CFTR modulator therapies that could benefit more people.

How do I know if a treatment is right for my child?

To learn if your child might benefit from a CFTR modulator or other treatment, speak to their doctor. In some cases, their doctor might order tests to learn more about your child’s condition and how they might react to the medication.

If CFTR modulators aren’t the right fit for your child, other treatments are available. For example, their doctor might prescribe:

  • mucus thinners
  • bronchodilators
  • antibiotics
  • digestive enzymes

In addition to prescribing medications, your child’s health team might teach you how to perform airway clearance techniques (ACTs) to dislodge and drain mucus from your child’s lungs.

The takeaway

Many different types of genetic mutations can cause CF. The specific types of genetic mutations that your child has can influence their symptoms and treatment plan. To learn more about your child’s treatment options, speak to their doctor. In most cases, their doctor will recommend genetic testing.