Disease Information

 

Familial pulmonary fibrosis (FPF) is described as two or more first or second degree relatives have a diagnosis of idiopathic interstitial pneumonitis.  There may be several different forms of IIP segregating in the family, however at least one member in the family will have idiopathic pulmonary fibrosis (IPF).

 

The clinical findings of IIP are1:

  • Bibasilar reticular abnormalities;
  • Ground glass opacities;
  • Diffuse nodular lesions on high-resolution computed tomography;
  • Abnormal pulmonary function studies;
    • Include evidence of restriction
      • Reduced VC with an increase in FEV1/FVC ratio
    •  May show impaired gas exchange
      • increased P(A-a)O2 with rest or exercise or decreased diffusion capacity of the lung for carbon monoxide (DLCO).

 

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Individuals with FPF usually present between age 50 and 70 years. Familial pulmonary fibrosis may be complicated by lung cancer; alveolar cell carcinoma, small cell carcinoma, and adenocarcinoma have been describe. (Reference***)

 

FPF is indistinguishable from other IIPs by physical exam and imaging studies.  It generally has a similar clinical course.  The unique characteristic of FPF is the family history. (Reference***)

 

The prevalence of idiopathic pulmonary fibrosis is approximately 1 in 5000 to 1 in 66004.   In the United States the prevalence was estimated at 1 in 7140 using a narrow case definition and data from a large healthcare claims database5.  It has been estimated that 2% -20% of cases of IPF are familial (***reference).6,7  The most common inheritance pattern is autosomal dominant with reduced penetrance. 8,9

 

References

  1. Travis et al. American ThoracicSociety/European Respiratory Society International Multidisciplinary Consensus: Classification of the Idiopathic Interstitial Pneumonias. Am J Respir Crit Care Med. 165(2):277-304 (2002).

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  4. Coultas et al., The epidemiology of interstitial lung diseases. Am J Respir Crit Care Med. 1994; 150: 967–72

  5. Raghu et al., Incidence and prevalence of idiopathic pulmonary fibrosis. Am J Respir Crit Care Med. 174: 810-6 (2006).

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  8. Armanios et al., Telomerase mutations in families with idiopathic pulmonary fibrosis. N Engl J Med 356:1317-1326 (2007).

  9. Tsakiri et al., Adult-onset pulmonary fibrosis caused by mutations in telomerase. Proc Natl Acad Sci USA 104:7552-7557 (2007).