MedWire News: Mutations in the dystrobrevin binding protein 1 gene (DTNBP1) are associated with bipolar disorder, say European researchers in findings that reinforce the genetic overlap between schizophrenia and bipolar disorder.

As there is evidence to suggest a degree of overlap in genetic susceptibility between schizophrenia and bipolar disorder, the DTNBP1 gene, which has been linked to schizophrenia, has come under scrutiny for its potential associations with bipolar disorder.

To investigate further, Darya Gaysina, from King’s College London, UK, and colleagues genotyped 515 bipolar disorder patients and 1316 ethnically matched healthy controls for eight single nucleotide polymorphisms (SNPs), conducting an association analysis in 452 bipolar disorder patients and 956 controls.

The results, published in the American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics, showed that two SNPs – rs760761 and rs3213207 – were significantly associated with bipolar disorder, at odds ratios of 1.26 and 1.41, respectively, although only the former survived Bonferroni correction with borderline significance.

Furthermore, the G-C-G haplotype of the combined SNPs rs16876571-rs2619539-rs3213207, and the G-C-G-T haplotype of the combined SNPs rs16876571-rs2619539-rs3213207-rs760761, were significantly associated with bipolar disorder.

“Our results are consistent with previous studies in terms of a general association between the DTNBP1 and bipolar disorder,” the researchers conclude.

“They also provide additional molecular genetic evidence that a portion of the genotypic overlap between schizophrenia and bipolar affective disorder is attributable to this gene.”

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