Common null variant, Arg192Stop, in a G-protein coupled receptor, olfactory receptor 1B1, associated with decreased serum cholinesterase activity.
OBJECTIVE
Non-functioning single nucleotide polymorphisms (nSNPs) that result in premature termination codons, that is null-alleles of the respective genes, may have phenotypic effects on clinical parameters. We conducted association studies involving several G-protein coupled receptors (GPCRs) that harbor nSNPs, using clinical parameters of liver function in a general population consisting of 2969 Japanese adults.


METHODS
SNP typings were performed with TaqMan and Invader assays. Quantitative associations between genotypes and clinical parameters were analyzed by analysis of variance. Linkage disequilibrium (LD) was tested by Haploview Version 3.3. Haplotype-based association was performed using the haplo.stats program.


RESULTS
A significant correlation (P = 0.0057) was identified between serum cholinesterase activity (CHE) and an nSNP (Arg192Stop) in the olfactory receptor (OR) 1B1 gene, a member of the GPCR gene family. This nSNP was associated with decreased serum CHE (P = 0.0013). LD analysis based on eight selected SNPs at the locus revealed three LD blocks. The Arg192Stop nSNP was located on the second LD block, which covered one-third of the 3'-portion of the gene.


CONCLUSIONS
These results suggested that the null-allele of OR1B1 might affect metabolism of serum cholinesterase in carriers of this nSNP.
Koyano
Satoru
S
Departments of Gastroenterology, Yamagata University School of Medicine, Yamagata, Japan.
Emi
Mitsuru
M
Saito
Takafumi
T
Makino
Naohiko
N
Toriyama
Sayumi
S
Ishii
Miho
M
Kubota
Isao
I
Kato
Takeo
T
Kawata
Sumio
S