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In 2009, a large, multi-sample replication study failed to find any significant association with Intelligence for this or other SNPs in CHRM2 [PMID 19418213].
[PMID 16000316] CHRM2 gene predisposes to alcohol dependence, drug dependence and affective disorders: results from an extended case-control structured association study. And the earlier [PMID 15229186]
[PMID 17160701] and [PMID 17081262] or this pdf poster show association between the CHRM2 gene and intelligence . In this study of ~300 Caucasians, the (T;T) genotype appeared to typically have a 4 point higher IQ than the (A;T) genotype, which had a 4 point higher IQ (on average) than the (A;A) genotype. A nearby SNP, rs324640, showed similar results to rs324650, and was in linkage disequilibrium (r2 = 0.90) with it. [PMID 17081262].
[PMID 19644963] Association of a variant in the muscarinic acetylcholine receptor 2 gene (CHRM2) with nicotine addiction
[PMID 20351719] Genetic variation in cholinergic muscarinic-2 receptor gene modulates M(2) receptor binding in vivo and accounts for reduced binding in bipolar disorder
[PMID 21176104] Association of CHRM2 polymorphisms with severity of alcohol dependence
[PMID 17373692] No evidence for association between 19 cholinergic genes and bipolar disorder.
[PMID 17996044] Exploring the functional role of the CHRM2 gene in human cognition: results from a dense genotyping and brain expression study.
[PMID 18634760] Uncovering genes for cognitive (dys)function and predisposition for alcoholism spectrum disorders: a review of human brain oscillations as effective endophenotypes.
[PMID 19181679] Depression Case Control (DeCC) Study fails to support involvement of the muscarinic acetylcholine receptor M2 (CHRM2) gene in recurrent major depressive disorder.