Point mutations in the human vitamin D receptor gene associated with hypocalcemic rickets.
Hypocalcemic vitamin D-resistant rickets is a human genetic disease resulting from target organ resistance to the action of 1,25-dihydroxyvitamin D3. Two families with affected children homozygous for this autosomal recessive disorder were studied for abnormalities in the intracellular vitamin D receptor (VDR) and its gene. Although the receptor displays normal binding of 1,25-dihydroxyvitamin D3 hormone, VDR from affected family members has a decreased affinity for DNA. Genomic DNA isolated from these families was subjected to oligonucleotide-primed DNA amplification, and each of the nine exons encoding the receptor protein was sequenced for a genetic mutation. In each family, a different single nucleotide mutation was found in the DNA binding domain of the protein; one family near the tip of the first zinc finger (Gly----Asp) and one at the tip of the second zinc finger (Arg----Gly). The mutant residues were created in vitro by oligonucleotide directed point mutagenesis of wild-type VDR complementary DNA and this cDNA was transfected into COS-1 cells. The produced protein is biochemically indistinguishable from the receptor isolated from patients.
Hughes
M R
MR
Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030.
Malloy
P J
PJ
Kieback
D G
DG
Kesterson
R A
RA
Pike
J W
JW
Feldman
D
D
O'Malley
B W
BW
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002117:Calcitriol / Q000378:metabolism; D002460:Cell Line; D002461:Cell Line, Transformed; D003062:Codon; D004247:DNA / Q000235:genetics / Q000378:metabolism; D005091:Exons; D005260:Female; D005784:Gene Amplification; D006720:Homozygote; D006801:Humans; D006996:Hypocalcemia / Q000235:genetics*; D015151:Immunoblotting; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000235:genetics* / Q000378:metabolism; D012279:Rickets / Q000235:genetics*; D014162:Transfection
D003062:Codon; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D004247:DNA; D002117:Calcitriol