When you think genetics, what’s the first condition that comes to mind? It may be a chromosomal disorder like Down syndrome or a single gene condition
such as sickle cell disease. But as the fields of genetics and genomics grow, we are learning more and more about more common disorders, many of which
are adult-onset conditions, and how genetics plays a role. One of those conditions is pulmonary fibrosis.
Julie Jones, PhD, of GGC’s DNA Diagnostic Laboratory recently had the opportunity to attend the Pulmonary Fibrosis Foundation (PFF) Summit in Nashville
with nearly 900 patients, caregivers, clinicians and researchers. Below is her experience interacting with this population of patients and families
who have more recently come to the attention of geneticists…
What is Pulmonary Fibrosis?
Pulmonary fibrosis (PF) – not to be confused with cystic fibrosis, a very different hereditary lung disease that presents in infancy – is a chronic and
progressive lung disease that affects 200,000 Americans and causes more than 40,000 deaths each year. Fifty-thousand new cases are diagnosed annually.
There is no known cure, and from the time of diagnosis the average life expectancy is 3 to 5 years. Symptoms of PF may include dry cough, shortness
of breath, discomfort in the chest, fatigue and weakness, and unexplained weight loss.
Pulmonary fibrosis is part of a family of related disorders called interstitial lung diseases. In PF, scar tissue builds up in the walls of the air sacs
of the lungs, and eventually the scar tissue makes it difficult for oxygen to get to the blood resulting in shortness of breath. As the disease progresses,
patients may require supplemental oxygen to breathe. Ultimately, the continual irreversible scarring results in respiratory failure and death.
What causes PF?
Pulmonary fibrosis may result from environmental or occupational exposures such as bacteria, molds, asbestos, silica, and coal dust. It can also be caused
by certain medications and radiation treatments. Many medical conditions including systemic lupus erythematosus, sarcoidosis, scleroderma, rheumatoid
arthritis, and pneumonia can lead to PF.
So how does genetics play a role?
Approximately 10-15% of individuals with PF have a relative who is also affected by the disease. A number of genes have been associated with pulmonary
fibrosis, and a pathogenic alteration within one of these genes can lead to the familial form of PF. Genetic factors have also been shown to play a
role in sporadic cases of pulmonary fibrosis. If a specific cause of PF is not identified, the disease is labeled as idiopathic pulmonary fibrosis.
What happened at the PFF Summit?
At the PFF Summit, individuals from 46 states and 12 countries attended sessions on topics ranging from the role of genetics in PF to the critical need
for earlier diagnosis of patients with this devastating lung disease. I had the chance to speak with many of the patients, and they all shared a similar
experience of having symptoms for many months and even years before they were finally diagnosed with the disease.
Early diagnosis is crucial so that patients have access to medications that have been shown to slow progression in individuals with mild to moderate disease.
Accurate diagnosis relies on high resolution CT scans and, in some cases, surgical lung biopsy (SLB); however, the risk of mortality associated with
SLB must be weighed carefully. Alternative, less invasive diagnostic procedures are needed so that a SLB may be avoided.
For approximately 20% of patients with PF, genetic testing may aid in the diagnosis and possibly eliminate the need for SLB.
What about treatment?
One of the other topics highlighted at this year’s PFF summit was personalized medicine. There is a growing body of evidence that genetic variants influence
the risk of developing PF as well as disease progression and response to therapies. In future clinical trials of treatments for PF, it will be essential
to account for genetic variation in order to determine the relationship between genotype and therapeutic response. This will be crucial in improving
and personalizing treatments for pulmonary fibrosis.
Should I have genetic testing for PF?
I attended the PFF summit in order to inform and educate clinicians and patients about genetic tests related to lung disorders. GGC’s Comprehensive Pulmonary
Panel tests for variants within 93 genes associated with inherited lung diseases. A subset of these genes are linked to pulmonary fibrosis. As new
genes are identified as being associated with pulmonary fibrosis, they will be added to the panel so that patients will have access to comprehensive
genetic testing. As with any genetic testing, it is important to discuss the potential risks and benefits of having this panel run with a qualified
genetic counselor and your clinician.
For more information regarding pulmonary fibrosis, please visit http://www.pulmonaryfibrosis.org.
By Julie R. Jones, PhD