The absence of both GM-CSF and SP-D in transgenic mice brought about a reduction of type II cell volume and number per lung, as well as a correction of the total volume of lamellar bodies per type II cell and lung, indicating that the alterations with respect to type II cells and the intracellular surfactant pool due to SP-D-deficiency are at least partly mediated by GM-CSF [9,43]. This evidence concerns the gene SFTPD and hyperinsulinemic hypoglycemia, familial, 4.