1), also lacked mature SP-C. This infant died at the age of 1 month from respiratory failure. This case suggests the presence of SP-B and SP-C processing defects arising by means other than from mutations of these genes, i.e. alterations in the protein processing machinery or in the lipid transporters, like ABCA3, as recently shown [27]. The other child (patient 1, Tabs. 1 and 3) is still alive with corticosteroids. This evidence concerns the gene ABCA3 and respiratory failure.