title: Confirmation of association between the Val66Met polymorphism in the brain-derived neurotrophic factor (BDNF) gene and bipolar I disorder.
abstract: Recent studies have indicated that the brain-derived neurotrophic factor (BDNF) gene is involved in the etiology of bipolar disorder (BPD). Two family-based association studies showed that the Val allele of the functional polymorphism Val66Met in the BDNF gene is associated with BPD; however, others could not confirm the results. Here we performed a replication study in an independent sample and tested the hypothesis that the Val66 allele in the BDNF gene confers susceptibility to bipolar I disorder (BPI). Six hundred twenty-one patients with BPI and 998 control subjects were genotyped for the Val66Met polymorphism. All cases and controls were of European descent. All BPI patients had a positive family history of affective disorder. The frequency of the Val allele was significantly increased in BPI patient when compared to controls (chi2 = 4.8; df = 1; P = 0.028; two-sided; OR = 1.22; 95% CI: 1.02-1.47). Results confirm previous findings and suggest that the Val allele increases risk for BPI in patients of European descent. Further studies are necessary to elucidate the involvement of the BDNF gene in the pathophysiology of BPD.
authors.affiliation: Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-6140, USA. lohoff@mail.med.upenn.edu
authors.forename: F W
authors.initials: FW
authors.lastname: Lohoff
authors.forename: T
authors.initials: T
authors.lastname: Sander
authors.forename: T N
authors.initials: TN
authors.lastname: Ferraro
authors.forename: J P
authors.initials: JP
authors.lastname: Dahl
authors.forename: J
authors.initials: J
authors.lastname: Gallinat
authors.forename: W H
authors.initials: WH
authors.lastname: Berrettini
mesh_terms: D000328:Adult; D000483:Alleles; D019943:Amino Acid Substitution; D001714:Bipolar Disorder / Q000235:genetics*; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D008715:Methionine / Q000235:genetics; D011110:Polymorphism, Genetic; D014633:Valine / Q000235:genetics*; D044465:White People
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D008715:Methionine; D014633:Valine