In 2009 and 2016, it was shown that very rare mutations in the genes encoding the surfactant proteins A2 and A1—respectively, SFTPA2 and SFTPA1—segregated with an ILD and adenocarcinoma phenotype in large families with multiple members with ILD occurring at a wide age range and/or adenocarcinoma only in adults [75,76]. Here, SFTPA2 is linked to adenocarcinoma.