Familial pulmonary fibrosis (FPF) is a rare form of idiopathic pulmonary fibrosis (IPF) which is a type of interstitial lung disease. Interstitial lung diseases result from damage to the interstitium of the lung (Fig. 1). The interstitium is the tissue wall between the air sacs, or alveoli, of the lung. Normally, this is a thin tissue layer with just a few cells in it, consisting of white blood cells and fibroblasts. For most causes of interstitial lung disease, something is believed to damage the lining of the alveoli, leading to inflammation in the interstitium. In addition, the fibroblasts in this layer then begin producing collagen, or scar tissue, in response to this damage.

There are hundreds of causes of interstitial lung disease. The table below (Table 1) is just a partial list of the more common causes. At the bottom of the list, there are several "idiopathic" forms of interstitial lung disease listed. This means that the cause is unknown. This website focuses on the most common of these idiopathic forms, usual interstitial pneumonia (UIP), but the other forms are discussed as well.

Connective Tissue Diseases

• Scleroderma
• Polymyositis-dermatomyositis
• Systemic Lupus Erythematosus
• Rheumatoid arthritis
• Mixed connective tissue disease
• Ankylosing spondylitis

Treatment or drug-induced

• Antibiotics ((furantoin, sulfasalazine)
• Antiarrhythmics (amiodarone, tocainide, propranolol)
• Anti-inflammatory agents (gold, penicillamine)
• Anticonvulsants (phenytoin)
• Chemotherapy agents (mitomycin C, bleomycin, busulfan, cyclophosphamide, Azathioprine, BCNU, methotrexate)
• Therapeutic radiation
• Oxygen
• Cocaine

Primary Diseases

• Sarcoidosis
• Eosinophilic granuloma
• Amyloidosis
• Lymphangitic carcinoma
• Bronchoalveolar carcinoma
• Pulmonary lymphoma
• Adult Respiratory Distress Syndrome
• Acquired immunodeficiency syndrome (AIDS)
• Bone marrow transplantation
• Postinfectious
• Respiratory bronchiolitis
• Eosinophilic pneumonia
• Diffuse alveolar hemorrhage syndrome

Occupational and Environmental

• Inorganic dusts
  • Asbestosis
  • Silicosis
  • Coal worker’s pneumoconiosis
  • Talc pneumoconiosis

• Organic dusts
  • Bird breeder’s lung
  • Farmer’s lung

Idiopathic Pulmonary Fibrosis (IPF)

UIP is also commonly referred to as idiopathic pulmonary fibrosis (IPF) even though this is a more general term. IPF is also known as cryptogenic fibrosing alveolitis. Other names used in the past but not used as much now are Hamman-Rich syndrome, diffuse interstitial pneumonitis, idiopathic interstitial pneumonitis, fibrosing alveolitis and many others. This disease will be referred to here as usual interstitial pneumonia or UIP. These idiopathic forms are separated from each other primarily by their different appearances under the microscope, but they also differ in other characteristics.

The definite diagnosis of UIP, in addition to a characteristic biopsy, requires the exclusion of other causes of interstitial lung disease listed in Table 1, typical abnormalities on pulmonary function tests, and typical changes on chest X-rays or CT scans.

Familial pulmonary fibrosis (FPF) is simply a form of UIP which appears to run in families rather than occurring randomly as most UIP does. FPF is defined as at least two members of a primary biological family (parent, child, sibling) having clinical features of UIP which is confirmed on biopsy. Other than this inherited pattern, FPF is exactly the same as UIP. Patients with FPF and UIP have the same symptoms, X-ray changes, tissue changes, treatment and prognosis. Examination of the relatives of those with FPF found that approximately 50% had evidence of lung inflammation even though they had no symptoms. Therefore, FPF is probably inherited as an autosomal dominant trait with variable penetrance. This means that about half would inherit the genes that make them susceptible, but one would not get disease (the effects of the genes would not "penetrate") unless they were also exposed to an appropriate irritant or trigger. However, no specific genes have been identified so far.

Please Click Here For The Glossary

• King TE, Cherniack RM, Schwarz MI. Idiopathic Pulmonary Fibrosis and Other Interstitial Lung Diseases of Unknown Etiology. In: Textbook of Respiratory Medicine, 2^nd Edition. Murray J and Nadel J (eds.) Philadelphia, WB Saunders, 1994, p. 1827-1849.

• Murphy A, O’Sullivan BJ. Familial fibrosing alveolitis. Irish Journal of Medical Sciences. 150:204-209, 1981.