Rare Lung Disease

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General Information about Rare Lung Diseases


Rare lung diseases, defined as a disease that affects less than 200,000 individuals, impacts individuals across a wide swath of society.   Rare lung diseases include a wide spectrum of disorders, including alpha-1 antitrypsin deficiency (AATD), lymphangioleimyomatosis (LAM), Tuberous sclerosis, pulmonary alveolar proteinosis (PAP) and hereditary interstitial lung diseases.  Many of the rare lung diseases have provided unique opportunities to investigate mechanisms shared by more common lung diseases.  For example, alpha 1 antitrypsin (AAT) deficiency is a rare disorder that causes pulmonary emphysema.  Investigations into the disease showed that mutations in the gene for AAT protein were responsible for the destructive lung disease.  This led to the discovery that AAT is a protein that inhibits elastases, enzymes which attack structural components of the lung,  and launched an entire field of investigations into the role of these enzymes in the development of emphysema, even in patients who do not have genetic deficiency of AAT and offer hope for future therapies to harness this destructive process. 

Another example of the impact of basic science research is our understanding of the pulmonary alveolar proteinosis, an uncommon lung disease where abnormal protein builds up in the alveoli and  impairs normal gas exchange. Until recently, the only treatment option was to perform  whole lung lavage-a procedure requiring general anesthesia, in which the lung is washed out with over 20 liters of fluid.  Patients required repeated lavages every 3-12 months because of disease relapse.  Recently, scientists developed a mouse model in which the gene encoding for the GM-CSF (granulocyte-monocyte colony stimulating factor) protein was inactivated or ‘knocked out.’  Surprisingly these mice developed a lung disease that resembled pulmonary alveolar proteinosis.  When investigators then measured the levels of GM-CSF in pulmonary alveolar proteinosis patients, the GM-CSF levels were found to be very low and the patients had antibodies to GM-CSF in their blood.  Thus, pulmonary alveolar proteinosis now is considered an autoimmune disease.  This unexpected discovery has led to improved and easier treatment by replacing the GM-CSF. 

These success stories were only possible because of the support of the community for research and education.   Because many of these diseases are poorly understand, it is imperative that we continue to support research and education for this diseases, and increase federal support.  Our ultimate goal is to improve medical care for patients afflicted with these diseases, and apply the lessons learned to patients afflicted with more common diseases.

Source: Lynn Schnapp, MD, Chair, ATS RCMB Assembly

Four Facts About Hermansky-Pudlak Syndrome
  1. Hermansky-Pudlak Syndrome is genetic disorder that causes Pulmonary Fibrosis in certain subtypes.  It is characterized by albinism, decreased visual acuity, nystagmus, a bleeding tendency and in some, a Crohn’s-like digestive problem. It occurs in all ethnic groups around the world, but it is one of the most common genetic disorders among people of Puerto Rican background.
  2. Pulmonary fibrosis occurs nearly 100 percent of the time in HPS gene types 1 and 4, although the age of onset varies. On average, symptoms begin to appear in the mid-thirties.
  3. Genetic testing for HPS can result in false negatives because not all HPS genes have been identified. For now, platelets must be reviewed under an electron microscope for the absence of delta granules in the membrane of the platelet cell.
  4. Bleeding during surgical procedures can be controlled with blood platelet transfusions.

(Source HPSnetwork.org)

Facts about Primary Ciliary Dyskinesia (PCD)

Primary ciliary dyskinesia or PCD (aka ‘Kartagener syndrome’ or ‘immotile cilia syndrome’) is a rare disease of the airways caused by inherited structural or functional defects in motile cilia. Cilia are a crucial component of mucociliary clearance which is a primary form of airway host defense. When cilia don’t move effectively, bacteria-laden mucus can collect in the airways, causing a vicious cycle of inflammation, infection, increased mucus production and eventual destruction of the airways. People with PCD develop bronchiectasis at an early age and battle progressive decline in lung function over their lifetimes. Ciliary motility is also critical in determining organ placement in embryonic development, so people with PCD may have anomalies in the placement or formation of their internal organs.  In some patients, congenital cardiac defects can occur.

PCD affects fewer than 20,000 people in the US (about 1:15,000).  Like many rare disorders, it is difficult to diagnose and significantly under-reported.  While not many people have PCD, everybody has cilia and we all rely on mucociliary clearance daily to keep our airways healthy.  PCD provides a natural laboratory for studying the role of ciliary function in lung health and what we learn in PCD has the potential to benefit millions.  We salute ATS PAR for acknowledging the importance of rare lung diseases research during Rare Lung Disease week. 

Source: Michael Knowles, MD
Source: www.PCDFoundation.org