However, at least in the upper airway, because there is no change in VDR expression with disease or VD3 deficiency it is possible that should local 1,25(OH)2D3 levels be restored to control levels, ample VDR expression would be present to promote activation of VD3-related signaling pathways in the upper airway. This evidence concerns the gene VDR and hyperinsulinemic hypoglycemia, familial, 4.