Gene variants linked to both bipolar disorder and schizophrenia
MedWire News: Variations in the D-amino acid oxidase activator gene (DAOA) are linked to the development of bipolar disorder and schizophrenia, although they account for only a part of genetic susceptibility, UK study findings suggest.
Previous studies have associated the DAOA/G30 locus or the neighboring region of chromosome 13q33.2 with both bipolar disorder and schizophrenia, while four single nucleotide polymorphisms (SNPs) at 12q24.11 have been linked to schizophrenia. However, the results have been conflicting.
Hugh Gurling, from University College London, and colleagues therefore genotyped 431 schizophrenia patients, 303 bipolar disorder patients, and 442 ancestrally matched controls with no history of mental disorder.
All participants were genotyped for 11 SNPs at the DAOA locus, with schizophrenia patients and controls also genotyped for three SNPs at the D-amino acid oxidase gene (DAO) locus on chromosome 12.
The results, published in the journal Behavioral and Brain Functions, reveal that the SNP rs3918342 (M23) at the DAOA locus was significantly associated with schizophrenia, bipolar disorder, and both conditions combined.
There was a trend toward association with schizophrenia for the SNPs rs3916967 (M14) and rs1421292 (M24), with the latter also marginally significantly associated with both conditions combined.
The team also found that there was a haplotypic association with schizophrenia for the markers rs778293 (M22), rs3918342 (M23), and rs1421292 (M42), with alleles G, T, A increasing the risk for schizophrenia at an estimated frequency of 1.8% in controls and 3.6% in patients. None of the three DOA SNPs were associated with schizophrenia.
The team concludes: “Our findings point to a role for DAOA in both schizophrenia and bipolar disorder. However, it is evident that this locus can account for only a small proportion of genetic susceptibility to these disorders.”
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By Liam Davenport