title: Association of genetic variation in CACNA1C with bipolar disorder in Han Chinese.
abstract: BACKGROUND
  A growing body of evidence highlights the existence of shared genetic susceptibility to both major depressive disorder (MDD) and bipolar disorder (BD), suggesting some potential genetic overlap between the disorders. Genome-wide association studies have identified consistent association of single nucleotide polymorphisms of the α-1 C subunit of the L-type voltage-gated calcium channel gene (CACNA1C) with MDD and BD, suggesting CACNA1C as a promising candidate gene for susceptibility to mood disorders. In the present study, we tested the association of CACNA1C with MDD and BD in Han Chinese.
  
  
  METHODS
  We genotyped three potentially functional polymorphisms in 635 MDD patients, 286 BD patients and 730 normal, control patients.
  
  
  RESULTS
  The genotype frequencies of SNP rs1051375 showed statistically significant differences between the BD and control groups (P=0.005). At the allele level, the difference of G allele frequency of rs1051375 between BD patients and control subjects was also significant (P=0.011; OR=1.30, 95% CI: 1.06-1.58). We found that GG genotype of rs1051375 carriers had a lower age at onset than those with the AG or AA genotype, and the mean±standard deviation ages at onset of GG, AG and AA carriers were 24.04±4.22, 25.76±4.75 and 25.78±4.33 years, respectively. Neither genotype nor allele frequencies of the three polymorphisms were found to be significantly different between the MDD patients and control subjects.
  
  
  CONCLUSIONS
  The relative small sample size in BD group should be considered a limitation of this study.
  
  
  CONCLUSIONS
  Our initial findings support a potential association of CACNA1C as a genetic risk factor for BD susceptibility.
authors.affiliation: Department of Psychiatry, Tongji Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Wu
authors.forename: Zuowei
authors.initials: Z
authors.lastname: Wang
authors.forename: Daihui
authors.initials: D
authors.lastname: Peng
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Wu
authors.initials: W
authors.lastname: Hong
authors.forename: Chengmei
authors.initials: C
authors.lastname: Yuan
authors.forename: Zezhi
authors.initials: Z
authors.lastname: Li
authors.forename: Shunying
authors.initials: S
authors.lastname: Yu
authors.forename: Yiru
authors.initials: Y
authors.lastname: Fang
mesh_terms: D000328:Adult; D017668:Age of Onset; D044466:Asian People / Q000235:genetics*; D001714:Bipolar Disorder / Q000235:genetics* / Q000503:physiopathology; D020746:Calcium Channels, L-Type / Q000235:genetics*; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D055106:Genome-Wide Association Study; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide
chemical_list: C079146:CACNA1C protein, human; D020746:Calcium Channels, L-Type
keywords: Age at onset; Bipolar disorder; CACNA1C; Major depressive disorder; Polymorphism