Abstract
Background: Idiopathic interstitial pneumonia (IIP) comprise a heterogeneous group of rare lung parenchyma disorders with high morbidity and mortality. They have been associated with an increased frequency of lung cancer. A genetic cause is identified in up to 20% of familial cases, telomerase and surfactant genes (SFTPA2, SFTPB, SFTPC, ABCA3) mutations being the first etiologies.
Objectives:This study investigates the implication of SFTPA1 (NM_005411) in 12 families affected by IPF and lung cancer.
Methods: SFTPA1 was sequenced by Sanger method in 12 unrelated index cases. An informed signed consent was obtained for each patient. New SFTPA1 variations were studied with functional experimentations.
Results: A heterozygous missense disease-causing mutation (p.Trp211Arg, W211R), in SFTPA1, that encodes the Surfactant Protein (SP)-A1, was identified in a large family. The affected members, aged 7 months to 59 years, presented with various forms of IIP, and adenocarcinoma. The W211R mutation segregated in a dominant pathway with the disease. The mutation involved an amino-acid that is located in the carbohydrate recognition domain (CRD) of SP-A1 and involved a residue invariant throughout evolution in SP-A1, but also in SP-A2 and in other CRD-containing proteins. The W211R mutation impaired SP-A1 secretion, and an abnormal expression pattern of SP-A was found in the alveolar epithelium of lung tissue from a patient carrying the SFTPA1 mutation.
Conclusion: This first report of the involvement of SFTPA1 in a Mendelian disorder unveils the key role of SP-A1 in the pathophysiology of IIP from infancy to elderly, and open up a new field of research on the mechanisms involved in IIP and lung cancer.
- Copyright ©the authors 2016
