Tryptophan missense mutation in the ligand-binding domain of the vitamin D receptor causes severe resistance to 1,25-dihydroxyvitamin D.
J Bone Miner Res
; 17(9): 1728-37, 2002 Sep.
Article
en En
| MEDLINE
| ID: mdl-12211444
In this study, two related young children, brother and sister, exhibited severe vitamin D-resistant rickets without alopecia. Sequence analysis of the total vitamin D receptor (VDR) cDNA from skin fibroblasts revealed a substitution of the unique tryptophan of the VDR by arginine at amino acid 286 (W286R). Cultured skin fibroblasts of the two patients expressed normal-size VDR protein (immunocytochemistry and Western blotting) and normal length VDR mRNA (Northern blotting). But, these fibroblasts, as well as COS-7 cells transfected with the W286R mutant, failed to bind 3H 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. The tryptophan substitution did not affect VDR trafficking toward the nucleus but abolished the 24-hydroxylase gene response to 1,25(OH)2D3, even at 10(-6) M concentrations. In conclusion, this case report of a new family with hereditary vitamin D-resistant rickets (HVDRR) emphasizes the crucial role of the VDR tryptophan for ligand binding and for transactivation of 1,25(OH)2D3 target genes. It clearly shows the clinical significance of this VDR amino acid for calcium homeostasis and bone mineralization. This observation suggests further that the presence of a stable VDR-bound ligand may not be obligatory for normal hair follicle development.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Calcitriol
/
Receptores de Calcitriol
/
Hipofosfatemia Familiar
Tipo de estudio:
Etiology_studies
Límite:
Animals
/
Child, preschool
/
Female
/
Humans
/
Infant
/
Male
Idioma:
En
Revista:
J Bone Miner Res
Asunto de la revista:
METABOLISMO
/
ORTOPEDIA
Año:
2002
Tipo del documento:
Article
País de afiliación:
Francia
Pais de publicación:
Estados Unidos