The fetal adrenal cortex lacks expression of the enzyme early on, thus mineralocorticoids (. aldosterone ) and glucocorticoids (. cortisol ) cannot be synthesized. This is significant because cortisol induces type II pneumocytes of the lungs to synthesize and secrete pulmonary surfactant ; without pulmonary surfactant to reduce the alveolar surface tension , premature neonates may die of neonatal respiratory distress syndrome . If delivery is unavoidable (. because of placental abruption , or pre-eclampsia / HELLP syndrome ), then glucocorticoids (. cortisol) can be administered.
Cheng et al. (2003) confirmed this mutation in the family of Clayton et al. (1987) and found it in a second consanguineous Saudi family. They determined that the 1057deltaCT mutation gives rise to a protein in which the first 346 amino acids of the normal protein are fused to a 5-residue extension. The mutation was found to produce mRNAs that were similar in size and amount to those derived from the normal gene but failed to encode an active enzyme when introduced into HEK293 cells. It was not known whether inactivation resulted from elimination of the normal C-terminal sequences or addition of the spurious residues.