Hereditary vitamin D-resistant rickets (HVDRR) is caused by mutations in the vitamin D receptor (VDR) gene. Arg274 located in the ligand binding domain (LBD) of VDR is responsible for anchoring 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)(2)D-3) by forming a hydrogen bond with the 1 alpha-hydroxyl group of 1 alpha,25(OH)(2)D-3. The Arg274Leu (R274L) mutation identified in patients with HVDRR causes a 1000-fold decrease in the affinity for 1 alpha,25(OH)(2)D-3, and dramatically reduces vitamin D-related gene expression. Recently, we successfully constructed fusion proteins consisting of split-luciferase and LBD of the VDR. The chimeric protein LucC-LBD-LucN, which displays the C-terminal domain of luciferase (LucC) at its N-terminus, can detect and discriminate between VDR agonists and antagonists. The LucC-LBD (R274L)LucN was constructed to screen high-affinity ligands for the mutant VDR (R274L). Of the 33 vitamin D analogs, 5 showed much higher affinities for the mutant VDR (R274L) than la,25(OH)2D3, and 2 alpha-[2-(tetrazol-2-ypethy1]-1 alpha,25-(OH)(2)D-3 showed the highest affinity. These compounds might be potential therapeutics for HVDRR caused by the mutant VDR (R274L). (C) 2016 Elsevier Ltd. All rights reserved.