CFTR-Related Metabolic Syndrome (CRMS)

You or your child has been diagnosed with CFTR-Related Metabolic Syndrome (CRMS). CFTR stands for cystic fibrosis transmembrane conductance regulator. Cystic fibrosis (CF) is a genetic (inherited) disease. CFTR is a protein made by the “CF gene” that acts as a channel to move salt in and out of the cells. 

The diagnosis of CRMS means that you or your child does not have CF. However, there are several reasons why it is still important to have regular checkups with a doctor who is a CF specialist.


What is CRMS?

When a person has a sweat test that gives an intermediate (borderline) result or a genetic test that shows only one CF gene, he or she is said to have CFTR-related metabolic syndrome (CRMS).

Your doctor may give you or your child a diagnosis of CRMS if:

  • The amount of salt in the sweat is higher than it is in most people, but not high enough to confirm a diagnosis of CF. This could mean that you or your child is at higher risk of having problems in the airways and sinuses; the intestines and pancreas; or the reproductive tract. 
  • You or your child has one or two CF gene mutations that don’t show any symptoms of CF, but could mean that you or your child is at higher risk of having problems in the parts of the body often affected by CF. 
back to top

What causes cystic fibrosis?

Cystic fibrosis (CF) is a genetic (inherited) disease. Genes give our bodies the instructions, or code, for all of our physical characteristics, such as eye color and whether our hair will be curly or straight.

Genes come in pairs. You receive one from your mother and one from your father. A change in the code in a gene is called a mutation. Some mutations don’t cause any problems at all. Some can cause diseases like CF. People with CF have a disease-causing mutation in each of their two CFTR genes — one mutation inherited from their mother and one mutation from their father. Read more about CF Genetics here.

back to top

What are the symptoms of cystic fibrosis?

The CFTR gene controls the salt channels in skin. People with CF have mutations that cause their sweat to be very salty. The CF gene also controls the salt channels in the:

  • Airways 
  • Intestines
  • Pancreas
  • Reproductive tract

People with CF get thick and sticky mucus in these parts of the body. Because of this thick mucus, people with CF get:

  • A chronic cough
  • Lung infections, such as pneumonia or bronchitis
  • Wheezing or shortness of breath
  • Poor growth/weight gain in spite of eating well
  • Frequent greasy, bulky stools or difficulty in bowel movements

back to top

What are the symptoms of CRMS?

Although we cannot clearly know the future health of a person with CRMS, he or she is likely to remain healthy. Some people with CRMS have problems in the airways or sinuses; the intestines and pancreas; or the reproductive tract. But we don’t know how many people with CRMS do not have these problems.

You should see your regular doctor and possibly your CF specialist if you or your child has any of these symptoms:

  • No weight gain
  • Loose stools, very bad gassiness or constipation that last more than 2 weeks
  • Very bad stomach aches
  • Coughing or wheezing that last more than 2 weeks

back to top

What can we do to keep our child healthy?

If you or your child has CRMS, the best thing to do is to have regular checkups with a CF specialist so that any health changes or problems can be found early and treated quickly.

As is true for everyone, people with CRMS should not be around tobacco smoke. All people 6 months of age and older should receive an influenza vaccine every year in the fall.

back to top

Additional Information

back to top

Updated 4/17/12