FOXO3A gene gene variants linked to bipolar disorder
MedWire News: Three single nucleotide polymorphisms (SNPs) in the forkhead box O3 gene (FOXO3A) are significantly associated with bipolar disorder susceptibility, but not with suicidal behaviour in patients with the mood condition, Brazilian research suggests.
Writing in the Journal of Affective Disorders, Marco Romano-Silva (Universidade Federal de Minas Gerais) and team explain: "Genetic variation plays an important role in bipolar disorder and suicide susceptibility. However, little is known about the genetic influence on the risk of suicide, particularly in bipolar disorder patients."
They add that previous studies have shown that FOXO3A plays a role in behavioral processes linked to anxiety and depression, suggesting that genetic polymorphisms in this gene "may have a possible role in bipolar disorder and suicidal behavior."
To investigate, the team studied 273 patients (30.6% men) with bipolar I or II disorder and 264 individuals (33.6% men) without the mood condition. Of the patients with bipolar disorder, 45.2% had a history of suicide attempts.
All of the participants were genotyped for the FOXO3A SNPs rs1536057, rs2802292, rs3813498, and rs1935952.
The researchers found that, overall, there were significant differences between bipolar disorder patients and controls regarding both the allele and genotype distribution of rs1536057, rs2802292, and rs1935952.
After correcting for permutation tests,these differences remained significant for all alleles, except for the rs2802292 allele association..
There were no significant differences between bipolar disorder patients and controls regarding either the allele or genotype distribution of rs3813498, however.
The researchers also found that there were no significant associations between any of the FOXO3A SNPs and suicidal behaviour in the bipolar disorder patients.
Romano-Silva and team conclude: "This study points out that FOXO3A SNPs confer susceptibility for bipolar disorder, but [do] not confer vulnerability for suicidal behavior."
They add: "Although our results indicate FOXO3A as a potential bipolar disorder candidate gene, further replications in other cohorts are needed to confirm the genetic association variation within this locus."
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By Mark Cowen