Alternative Names
CF; Cystic fibrosis of pancreas; Fibrocystic Disease of Pancreas; Mucoviscidosis
Symptoms & Characteristics
Cystic fibrosis (commonly called CF) is a genetic condition that affects the mucus and sweat glands. Mucus is a slippery substance that lubricates and protects the linings of the lungs, digestive tract, reproductive tract, and other organs and tissues. CF causes mucus to be thick and sticky, which in turn gets stuck and causes obstructions in the affected organs and tissues. Some of the major affected organs are the lungs, pancreas, and sex organs.
- In the lungs, this mucus makes it easy for bacteria to grow causing recurrent lung infections and tissue damage including the formation of scar tissue (called fibrosis) and cysts.
- In the pancreas, this mucus may make it difficult for the pancreas to work properly blocking important enzymes from aiding in the digestion of food. Digestion problems can result in diarrhea, malnutrition and weight loss, and poor growth.
- In male sex organs, this mucus may block the tubes that carry sperm (called the vas deferens) causing infertility. This condition is called congenital bilateral absence of the vas deferens (CBAVD) if both vas deferens are affected, and congenital unilateral AVD if only one is affected. Female sex organs may also be affected, but female infertility is less common,
The symptoms and severity of CF vary widely even among affected members of the same family. Some people have serious problems from birth. For example, a blockage of the intestines, called meconium ileus, may be a sign of CF in babies. Other people do not develop symptoms until childhood or even adulthood.
Treatment
CF is a chronic, life-long condition. Although there is currently no cure for CF, treatments have improved greatly in the last 15 years. Most deaths from CF used to occur in children and teenagers. Today, with improved treatments, people who have CF live, on average to be 32 years old.
How Common Is It?
CF is more common in people of certain ethnic backgrounds.
| Cystic Fibrosis Incidence |
| Ethnicity |
Number of Affected People |
| Caucasians |
1 in 2,500 |
| Hispanics |
1 in 8,000 |
| African-Americans |
1 in 15,000 |
| Asians |
1 in 32,000 |
Genetics & Inheritance
Cystic fibrosis is caused by mutations in a gene called CFTR on the chromosome 7 at the location q31.2. There are over a thousand documented mutations in the CFTR gene, which is partly why there is so much variability in the symptoms and severity of CF.
- The most common mutation in Caucasians is called the deltaF508 mutation.
- Some mutations are straightforward and will inevitably cause disease symptoms.
- Some mutations are not straightforward and may or may not cause disease symptoms.
- Some mutations increase the chance to develop specific symptoms of CF, like pancreatic and digestive issues.
- Some mutations or even normal genetic variations cause disease symptoms only when present in conjunction with other specific mutations.
We all have two copies of the CFTR gene - one from each parent. In CF, it is generally necessary to have two mutations, one in each gene copy, to be affected. This is called autosomal recessive inheritance.
- Both parents of an affected person are obligate carriers (each have only one mutation). Two carriers have a 25% chance with each pregnancy to have an affected child, but typically do not have symptoms themselves.
- Without a family history, the chance to be a carrier is determined by a person's ethnic background.
| Cystic Fibrosis Carrier Risk |
| Ethnicity |
Number of Carriers |
| Caucasians |
1/25 |
| Hispanics |
1/48 |
| African-Americans |
1/60 |
| Asians |
1/90 |
There are many other genetic conditions, which have symptoms that overlap with cystic fibrosis. A genetic consultation with a trained genetic professional is important for a complete evaluation, accurate diagnosis, as well as discussion of the benefits and limitations of testing and recurrence risk.
Genetic Testing
Clinical genetic testing for cystic fibrosis can be broken down into two categories: diagnostic testing and carrier testing. The complexity of CF testing increases with the number of mutations looked for in the CFTR gene.
Diagnostic testing may be used to confirm or rule out a clinical diagnosis in a person suspected to have the disorder.
- Complete CFTR gene sequencing is the method used to look at every "letter" of the gene and will detect the most amount of mutations present. Gene sequencing is typically used when a person has a clinical diagnosis of CF, but standard genetic testing for the more common mutations is negative or only identified one of their two mutations.
Carrier testing typically looks for the most common mutations.
- Providers currently offer testing for 25 mutations to 96 mutations. Each provider makes its own decision as to how many mutations they look for.
- As only a few mutations are tested for, if a person has negative carrier testing, their chance to be a carrier is greatly reduced, but never actually zero. Their residual risk to still be a carrier is based on a number of factors. Some of these factors include if there is a positive family history of CF, their ethnic background and how many mutations were tested for.
- In 2001, The American College of Obstetricians and Gynecologists (ACOG) recommended that physicians offer all couples who are pregnant or planning to become pregnant a blood test for cystic fibrosis carrier testing.
Carrier testing for cystic fibrosis is available online (over the internet). Go to the Tests tab to link to the best providers, compare providers and read provider reviews
Diagnostic testing and carrier testing for cystic fibrosis is available through an in person genetic consultation. Use our find a genetic professional directory to locate a trained genetic professional in your area.
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