Understanding cystic fibrosis

Cystic fibrosis is an uncommon genetic disorder. It primarily affects the respiratory and digestive systems. Symptoms often include chronic cough, lung infections, and shortness of breath. Children with cystic fibrosis may also have trouble gaining weight and growing.

Treatment revolves around keeping the airway clear and maintaining adequate nutrition. Health problems can be managed, but there’s no known cure for this progressive illness.

Until late in the 20th century, few people with cystic fibrosis lived beyond childhood. Improvements in medical care have increased life expectancy by decades.

Cystic fibrosis is a rare disease. The most affected group is Caucasians of northern European ancestry.

About 30,000 people in the United States have cystic fibrosis. The disease affects about 1 in 2,500 to 3,500 white newborns. It’s not as common in other ethnic groups. It affects about 1 in 17,000 African-Americans and 1 in 100,000 Asian-Americans.

It’s estimated that 10,500 people in the United Kingdom have the disease. About 4,000 Canadians have it and Australia reports about 3,300 cases.

Worldwide, about 70,000 to 100,000 people have cystic fibrosis. It affects males and females at about the same rate.

In the United States, about 1,000 new cases are diagnosed each year. About 75 percent of new diagnoses happen before age 2.

Since 2010, it’s mandatory for all doctors in the United States to screen newborns for cystic fibrosis. The test involves collecting a blood sample from a heel prick. A positive test can be followed up with a “sweat test” to measure the amount of salt in the sweat, which can help secure the diagnosis of cystic fibrosis.

In 2014, more than 64 percent of people diagnosed with cystic fibrosis were diagnosed through newborn screening.

Cystic fibrosis is one the most common life-threatening genetic diseases in the United Kingdom. Approximately 1 in 10 people are diagnosed before or soon after birth.

In Canada, 50 percent of people with cystic fibrosis are diagnosed by 6 months of age; 73 percent by 2 years of age.

In Australia, most people with cystic fibrosis are diagnosed before they’re 3 months old.

Cystic fibrosis can affect people of any ethnicity and in any region in the world. The only known risk factors are race and genetics. Among Caucasians, it’s the most common autosomal recessive disorder. Autosomal recessive genetic inheritance pattern means that both parents need to be at least carriers of the gene. A child will only develop the disorder if they inherit the gene from both parents.

According to John Hopkins, the risk of certain ethnicities carrying the faulty gene is:

  • 1 in 29 for Caucasians
  • 1 in 46 for Hispanics
  • 1 in 65 for African-Americans
  • 1 in 90 for Asians

The risk of having a child born with cystic fibrosis is:

  • 1 in 2,500 to 3,500 for Caucasians
  • 1 in 4,000 to 10, 000 for Hispanics
  • 1 in 15,000 to 20,000 for African-Americans
  • 1 in 100,000 for Asians

There’s no risk unless both parents carry the defective gene. When that happens, the Cystic Fibrosis Foundation reports the inheritance pattern for children as:

In the United States, about 1 in 31 people are carriers for the gene. Most people don’t even know it.

Cystic fibrosis is caused by defects in the CFTR gene. There are over 2,000 known mutations for cystic fibrosis. Most are rare. These are the most common mutations:

Gene mutationPrevalence
F508delaffects up to 88 percent of people with cystic fibrosis worldwide
G542X, G551D, R117H, N1303K, W1282X, R553X, 621+1G->T, 1717-1G->A, 3849+10kbC->T, 2789+5G->A, 3120+1G->Aaccounts for less than 1 percent of cases across the United States, Canada, Europe, and Australia
711+1G->T, 2183AA->G, R1162Xoccurs in over 1 percent of cases in Canada, Europe, and Australia

The CFTR gene makes proteins that help move salt and water out of your cells. If you have cystic fibrosis, the protein doesn’t do its job. The result is a buildup of thick mucus that blocks ducts and airways. It’s also the reason people with cystic fibrosis have salty perspiration. It can also affect how the pancreas works.

You can be a carrier of the gene without having cystic fibrosis. Doctors can look for the most common genetic mutations after taking a blood sample or cheek swab.

It’s difficult to estimate the cost of treating cystic fibrosis. It varies according to the severity of disease, where you live, insurance coverage, and what treatments are available.

In 1996, healthcare costs for people with cystic fibrosis were estimated at $314 million per year in the United States. Depending on severity of disease, individual expenses ranged from $6,200 to $43,300.

In 2012, the U. S. Food and Drug Administration approved a specialty drug called ivacaftor (Kalydeco). It’s designed for use by the 4 percent of people with cystic fibrosis who have the G551D mutation. It carries a price tag of about $300,000 per year.

The cost of a lung transplant varies from state to state, but it can reach several hundred thousand dollars. Transplant medications must be taken for life. Expenses due to lung transplant can reach $1 million in the first year alone.

Expenses also vary according to health coverage. According to the Cystic Fibrosis Foundation, in 2014:

  • 49 percent of people with cystic fibrosis under age 10 were covered by Medicaid
  • 57 percent between the ages of 18 and 25 were covered under a parent’s health insurance plan
  • 17 percent aged 18 to 64 were covered under Medicare

A 2013 Australian study put the mean annual healthcare cost of treating cystic fibrosis at $15,571 U.S. dollars. Costs ranged from $10,151 to $33,691 depending on the severity of disease.

People with cystic fibrosis should avoid being very close to others who have it. That’s because each person has different bacteria in their lungs. Bacteria that are not harmful to one person with cystic fibrosis can be quite dangerous to another.

Other important facts about cystic fibrosis:

  • Diagnostic evaluation and treatment should begin immediately upon diagnosis.
  • 2014 was the first year the Cystic Fibrosis Patient Registry included more people over the age of 18 than under.
  • 28 percent of adults report anxiety or depression.
  • 35 percent of adults have cystic fibrosis-related diabetes.
  • 1 in 6 people over age 40 have had a lung transplant.
  • 97 to 98 percent of men with cystic fibrosis are infertile, but sperm production is normal in 90 percent. They can have biological children with assisted reproductive technology.

Until recently, most people with cystic fibrosis never made it to adulthood. In 1962, the predicted median survival was about 10 years.

With today’s medical care, the disease can be managed much longer. Now it’s not unusual for people with cystic fibrosis to live into their 40s, 50s, or beyond.

An individual’s outlook depends on severity of symptoms and effectiveness of treatment. Lifestyle and environmental factors may play a role in disease progression.

Keep reading: Cystic fibrosis »