By Cari Nierenberg - Live Science Contributor
Cystic fibrosis is a genetic disorder that causes mucus-producing organs to malfunction and produce abnormally thick, sticky mucus. This causes problems in those organs, such as the lungs, the pancreas and the organs of the digestive system.
About 30,000 people in the United States have cystic fibrosis, and more than 75% of those affected are diagnosed by age 2, according to the Cystic Fibrosis Foundation.
In healthy people, mucus is thin and slippery. In people with cystic fibrosis, the substance is is abnormally thick and builds up in the lungs, making breathing difficult. Thick mucus also creates a breeding ground for bacteria, which can often lead to serious lung infections, said Dr. Mary Shannon Fracchia, a pediatric pulmonologist and co-director of the Cystic Fibrosis Center at MassGeneral Hospital for Children in Boston.
Too much thick mucus in the pancreas blocks the pathway for digestive enzymes to reach the intestines. Without these enzymes, the intestines can't properly absorb nutrients from food, leading to difficulty gaining weight and a slower growth rate in children with the disorder.
Besides affecting organs that produce mucus, cystic fibrosis also influences the sweat glands. People with the disease may have two to five times the normal amount of salt in their sweat, according to Children's Hospital of Pittsburgh. Parents may say they taste salt when kissing a child who has the disorder.
In some people, cystic fibrosis also harms the liver and reproductive system.
The cause of cystic fibrosis is genetics, because a person needs to inherit a copy of a defective gene from both parents to develop the condition, Fracchia said. This defective gene, called the cystic fibrosis transmembrane conductance regulator (CFTR), was first identified in 1989, according to the Cystic Fibrosis Foundation.
People with cystic fibrosis have a mutation in both copies of the CFTR gene (one copy inherited from each parent). People who have one copy of the defective CFTR gene, inherited from only one parent, become carriers of the disease. Carriers don't have any symptoms of cystic fibrosis, but they can pass the CFTR gene on to their children.
If both parents are carriers of cystic fibrosis and have a child, there is a 1 in 4 chance that the child will have the disease, Fracchia told Live Science.
The defective CFTR gene produces a faulty protein that affects the movement of chloride — a component of salt, or sodium chloride — across cell membranes, according to the Cystic Fibrosis Foundation. This alters the flow of salt and water into and out of cells, causing problems in glands that produce mucus and sweat.
The CFTR gene is most common in white people of Northern European descent, but other ethnic populations can also develop the disease.
The lungs and pancreas are the organs most affected by cystic fibrosis, leading to breathing and digestive problems. Symptoms of cystic fibrosis can vary from one person to another, depending on the severity of the disease.
According to the Cystic Fibrosis Foundation, symptoms and complications may include:
Respiratory symptoms
Digestive symptoms
Sweat gland complications
Reproductive complications
A blood test for cystic fibrosis is first performed at birth. A blood sample is checked for certain biomarkers of the disease as part of routine newborn screening in all 50 states, according to the Mayo Clinic. If there is a positive result, doctors will perform a genetic test to confirm diagnosis.
Once the infant is at least 2 weeks old, doctors may follow up with a sweat test, which measures the amount of chloride in sweat collected from a small area of skin. People with the disease have higher than normal amounts of chloride in their sweat.
Other diagnostic tests may be done depending on a person's symptoms; these tests can include pancreatic function tests, chest X-rays and pulmonary function tests to measure how well the lungs work.
The main goals of treatment for cystic fibrosis are to prevent and treat infections, keep lungs and airways as clear as possible, and maintain adequate calories and nutrition, according to Children's Hospital of Pittsburgh.
Every year, the life expectancy for people with cystic fibrosis is getting longer, Fracchia told Live Science. The current life expectancy for someone with the disease is 41 to 42 years, Fracchia said.
According to the Mayo Clinic, treatment for lung problems may include:
Treatment for digestive problems may include: