Association of A118G polymorphism in the μ-opioid receptor gene with smoking behaviors: a meta-analysis

Association of OPRM1 with addiction: a review on drug, alcohol and smoking addiction in worldwide population

Background

Drugs are chemicals which can disrupt the nerve cell functions of the brain. The present study aims to investigate the addiction related gene (OPRM1) in three types of addiction—drugs, alcohol and smoking. Pathway for the addiction was ascertained through KEGG database, and the hotspot mutations for various populations were identified from Gnomad-exomes database. In silico analyses like SIFT, Polyphen, Hope, I-mutant and mutation taster were performed to understand the amino acid substitution, protein function, stability and pathogenicity of the variants.

Main body

Addiction-related variants were found in exons 1, 2 and 3, while the exon 4 did not exhibit any addiction related variation. Among all the variants from this gene, rs1799971 (A118G) polymorphism was the most commonly studied variation for addiction in different populations worldwide. Population-wise allele and genotype frequencies, demographic and epidemiological studies have also been performed from different populations, and the possible association of these variants with addiction was evaluated.

Conclusion

Our findings suggest that OPRM1 polymorphism impact as pharmacogenetic predictor of response to naltrexone and can also address the genetic predisposition related to addiction in human beings.

No genetic association between A118G polymorphism of μ-opioid receptor gene and schizophrenia and bipolar disorders

BACKGROUND

Schizophrenia (SZ) and bipolar disorder (BD) are chronic and multifactorial psychiatric disorders that might be affected by different genes in combination with environmental factors. There is evidence of association between polymorphisms of μ-opioid receptor gene (OPRM1) with these disorders.

OBJECTIVES

The aim of this study was to investigate the genetic association between OPRM1 A118G SNP in SZ and BD patients in comparison with healthy controls (HCs).

MATERIALS AND METHODS

One single-nucleotide polymorphism in OPRM1 was genotyped using TaqMan real-time PCR assay in 203 SZ and BD patients and 389 HCs.

RESULTS

There was no statistically significant difference in genotypic and allelic frequencies of OPRM1 A118G SNP between HCs and SZ/BD patients.

CONCLUSIONS

To find the underlying genetic factors associated with these complex disorders, further studies need to be conducted using larger sample size, different genetic populations, and different gene variations.