Genetic factors in pulmonary fibrotic disorders.

Identifying genetic determinants of pulmonary fibrotic disorders remains at an early stage of evolution. It is now well-recognized that "pulmonary fibrosis" covers a broad range of lung diseases, including most topically the idiopathic interstitial pneumonias that have been classified recently. Additionally, it is recognized that the fibrosing lung disorders that are seen in the rheumatological diseases, notably systemic sclerosis, are quite different from those of the idiopathic variety. Defining clinical phenotype is an important prerequisite to the identification of genetic determinants associated with individual diseases, but it is important to acknowledge that there may be determinants of global lung fibrosis and that other factors drive diseases down specific, more individual disease pathways. Current association studies are encouraging but far from conclusive for a variety of reasons, including small numbers, poor controls, and curious candidate selection. The results of the ongoing multicenter familial linkage study in the United States should provide several candidate genes that will spur further studies of sporadic disease in, it is hoped, a more internationally coordinated effort.