|A service of the U.S. National Library of Medicine®|
Idiopathic pulmonary fibrosis
On this page:
Reviewed October 2010
What is idiopathic pulmonary fibrosis?
Idiopathic pulmonary fibrosis is a chronic, progressive lung disease. This condition causes scar tissue (fibrosis) to build up in the lungs, which makes the lungs unable to transport oxygen into the bloodstream effectively. The disease usually affects people between the ages of 50 and 70.
The most common signs and symptoms of idiopathic pulmonary fibrosis are shortness of breath and a persistent dry, hacking cough. Many affected individuals also experience a loss of appetite and gradual weight loss. Some people with idiopathic pulmonary fibrosis develop widened and rounded tips of the fingers and toes (clubbing).
Over time, scarring of the lungs increases until the lungs can no longer provide enough oxygen to the body's organs and tissues. Some people with idiopathic pulmonary fibrosis develop other serious lung conditions, including lung cancer, blood clots in the lungs (pulmonary emboli), pneumonia, or high blood pressure in the blood vessels that supply the lungs (pulmonary hypertension). Most affected individuals survive 3 to 5 years after their diagnosis. However, the course of the disease is highly variable; some affected people become seriously ill within a few months, while others may live with the disease for a decade or longer.
In most cases, idiopathic pulmonary fibrosis occurs in only one person in a family. These cases are described as sporadic. However, a small percentage of people with this disease have at least one other affected family member. When idiopathic pulmonary fibrosis occurs in multiple members of the same family, it is known as familial pulmonary fibrosis.
How common is idiopathic pulmonary fibrosis?
Idiopathic pulmonary fibrosis has an estimated prevalence of 13 to 20 per 100,000 people worldwide. About 100,000 people are affected in the United States, and 30,000 to 40,000 new cases are diagnosed each year.
Familial pulmonary fibrosis is less common than the sporadic form of the disease. Only a small percentage of cases of idiopathic pulmonary fibrosis appear to run in families.
What genes are related to idiopathic pulmonary fibrosis?
The cause of idiopathic pulmonary fibrosis is unknown, although the disease probably results from a combination of genetic and environmental factors. It is likely that genetic changes increase a person's risk of developing idiopathic pulmonary fibrosis, and then exposure to certain environmental factors triggers the disease.
Changes in several genes have been suggested as risk factors for idiopathic pulmonary fibrosis. Most of these genetic changes account for only a small proportion of cases. However, mutations in genes known as TERC and TERT have been found in about 15 percent of all cases of familial pulmonary fibrosis and a smaller percentage of cases of sporadic idiopathic pulmonary fibrosis. The TERC and TERT genes provide instructions for making components of an enzyme called telomerase, which maintains structures at the ends of chromosomes known as telomeres. It is not well understood how defects in telomerase are associated with the lung damage characteristic of idiopathic pulmonary fibrosis.
Researchers have also examined environmental risk factors that could contribute to idiopathic pulmonary fibrosis. These factors include exposure to wood or metal dust, viral infections, certain medications, and cigarette smoking. Some research suggests that gastroesophageal reflux disease (GERD) may also be a risk factor for idiopathic pulmonary fibrosis; affected individuals may breathe in (aspirate) stomach contents, which over time could damage the lungs.
See a list of genes associated with idiopathic pulmonary fibrosis.
How do people inherit idiopathic pulmonary fibrosis?
Most cases of idiopathic pulmonary fibrosis are sporadic; they occur in people with no history of the disorder in their family.
Familial pulmonary fibrosis appears to have an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means one copy of an altered gene in each cell is sufficient to cause the disorder. However, some people who inherit the altered gene never develop features of familial pulmonary fibrosis. (This situation is known as reduced penetrance.) It is unclear why some people with a mutated gene develop the disease and other people with the mutated gene do not.
Where can I find information about diagnosis or management of idiopathic pulmonary fibrosis?
These resources address the diagnosis or management of idiopathic pulmonary fibrosis and may include treatment providers.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about idiopathic pulmonary fibrosis?
You may find the following resources about idiopathic pulmonary fibrosis helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for idiopathic pulmonary fibrosis?
What if I still have specific questions about idiopathic pulmonary fibrosis?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding idiopathic pulmonary fibrosis?
acute ; autosomal ; autosomal dominant ; cancer ; cell ; chronic ; cryptogenic ; diagnosis ; enzyme ; familial ; fibrosis ; gastroesophageal reflux ; gastroesophageal reflux disease ; gene ; GERD ; hypertension ; idiopathic ; inherit ; inheritance ; oxygen ; pattern of inheritance ; penetrance ; pneumonia ; prevalence ; pulmonary ; risk factors ; sporadic ; stomach ; tissue
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (10 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.