rs4950

This variant is located in the CHRNB3 gene.

GWAS Catalog Trait Associations (1)

Genome-wide significant associations (p < 5×10⁻⁸) from the NHGRI-EBI GWAS Catalog.

nicotine dependence

Allele A
OR 0.02
p 2.0e-9
N 58,000
Large GWAS
multi-ancestry

Research that mentions this SNP (2)

Risk gene variants for nicotine dependence in the CHRNA5CHRNA3CHRNB4 cluster are associated with cognitive performance
AssociationN=492Georg Winterer et al.(2010)· American Journal of Medical Genetics Part B: Neuropsychiatric Genetics

This population-based study examined natural selection on nicotinic receptor gene clusters (CHRNB3-A6 on chromosome 8 and CHRNA5-A3-B4 on chromosome 15) using 1000 Genomes data from three populations. Using Tajima's D and integrated haplotype score (iHS) tests, the authors found strong evidence for positive selection in the CHRNB3-A6 region and moderate evidence in CHRNA5-A3-B4. These regions harbor variants previously associated with nicotine dependence (rs16969968, rs1451240) and cocaine dependence. To understand the target of selection, the authors tested variants in COGA subjects (N=492) for association with cognitive phenotypes (WAIS tests) and found one significant association: rs7017612 with WAIS Digit Symbol score (β=0.43, p=0.003), suggesting memory and learning may be the driving force behind selection.

Traits studied:Alcohol dependenceCocaine dependenceCognitive functionLearningMemoryNicotine dependenceProcessing speed
Multiple distinct risk loci for nicotine dependence identified by dense coverage of the complete family of nicotinic receptor subunit (CHRN) genes
AssociationN=1,929Nancy L. Saccone et al.(2009)· American Journal of Medical Genetics Part B: Neuropsychiatric Genetics

This comprehensive association study of 226 SNPs across all 16 nicotinic receptor subunit (CHRN) genes identified four distinct genetic loci significantly associated with nicotine dependence in 1050 cases and 879 controls of European descent. The two most significant associations were rs16969968 (CHRNA5, non-synonymous, p=0.00013, OR=1.30) and rs578776 (CHRNA3, p=0.00011, OR=1.34) in the CHRNA5-CHRNA3-CHRNB4 cluster; one locus in the CHRNB3-CHRNA6 cluster tagged by rs13277254 (p=0.00010); and a novel locus in the CHRND-CHRNG cluster tagged by rs12466358 (p=0.00027). Joint analyses confirmed statistical independence of the two CHRNA5-CHRNA3-CHRNB4 signals.

Traits studied:Cigarette consumptionNicotine dependenceSmoking behavior

About CHRNB3

The nicotinic acetylcholine receptors (nAChRs) are members of a superfamily of ligand-gated ion channels that mediate fast signal transmission at synapses. The nAChRs are (hetero)pentamers composed of homologous subunits. The subunits that make up the muscle and neuronal forms of nAChRs are encoded by separate genes and have different primary structure. There are several subtypes of neuronal nAChRs that vary based on which homologous subunits are arranged around the central channel. They are classified as alpha-subunits if, like muscle alpha-1 (MIM 100690), they have a pair of adjacent cysteines as part of the presumed acetylcholine binding site. Subunits lacking these cysteine residues are classified as beta-subunits (Groot Kormelink and Luyten, 1997 [PubMed 9009220]). Elliott et al. (1996) [PubMed 8906617] stated that the proposed structure for each subunit is a conserved N-terminal extracellular domain followed by 3 conserved transmembrane domains, a variable cytoplasmic loop, a fourth conserved transmembrane domain, and a short C-terminal extracellular region.[supplied by OMIM, Apr 2010]

View all CHRNB3 variants →

Gene information from NCBI Gene. Variant classifications from ClinVar.

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