[Arginine-glutamine replacement at residue 57 of NADH-cytochrome b5 reductase in Chinese hereditary methemoglobinemia].
OBJECTIVE
To elucidate the molecular mechanism of NADH cytochrome b5 reductase (Cytb5R) deficiency in hereditary methemoglobinemia.


METHODS
Cytb5R cDNA was cloned from white blood cells from patient with hereditary methemoglobinemia by RT-PCR method, and the genomic DNA from 3 pedigrees with hereditary methemoglobinemia were analyzed by restriction enzyme analysis.


RESULTS
On sequencing the cDNA, two missense mutation were found. One is CGG-->CAG at codon 57 of exon 3, caused Arg-Gln replacement. The other is GAG-->GGG at codon 222 of exon 8. The former mutation abolishes the Msp I recognition site which was confirmed in two of three hereditary methemoglobinemia family. The latter mutation generates a recognition site for Bsi Y I. Amplification of exon 8 by PCR followed by digestion with Bsi Y I revealed no mutation in all patients from the three families.


CONCLUSIONS
Arg57-Gln replacement is responsible for Cytb5R deficiency in the two Chinese pedigrees.
Huang
C
C
Center for Medical Laboratory, PLA, Fuzhou General Hospital, Fuzhou 350001.
Xie
Y
Y
Wang
Y
Y
Wu
Y
Y
Ye
Y
Y
Zhu
Z
Z
D000328:Adult; D019943:Amino Acid Substitution; D001120:Arginine; D044466:Asian People / Q000235:genetics*; D016022:Case-Control Studies; D003001:Cloning, Molecular; D042966:Cytochrome-B(5) Reductase / Q000737:chemistry* / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics; D005973:Glutamine; D006801:Humans; D008708:Methemoglobinemia / Q000201:enzymology / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
D018076:DNA, Complementary; D005973:Glutamine; D001120:Arginine; D042966:Cytochrome-B(5) Reductase