Functional and physiological consequences of StAR deficiency: role in lipoid congenital adrenal hyperplasia.

The steroidogenic acute regulatory (StAR) protein is essential for all hormone-stimulated steroid biosynthesis. Accordingly, its absence gives rise to the most severe form of congenital adrenal hyperplasia (CAH), lipoid CAH. This life-threatening condition typically manifests itself in the perinatal period. Partial loss-of-function StAR mutations incompletely manifest the condition later in life and are a cause of familial glucocorticoid deficiency type 3. Here, we discuss StAR, its expression pattern and the clinical consequences of the loss of its activity.