Genetic utility of broadly bipolar schizoaffective disorder as a diagnostic concept

Hamshere, M. L., Green, E. K., Jones, I. R., Moskvina, V., Kirov, G., Grozeva. D., Nikolov, I., Vukcevic, D., Caesar, S., Gordon-Smith, K., Fraser, C., Russell, E., Breen, G., St Clair, D., Collier, D. A., Young, A. H., Ferrier, I. N., Farmer, A., McGuffin, P., Wellcome Trust Case Control Consortium, Brown, M. A., Bradbury, L., Holmans P. A., Owen, M. J., O'Donovan, M. C. and Craddock, N. (2009) Genetic utility of broadly bipolar schizoaffective disorder as a diagnostic concept. British Journal of Psychiatry, 195 1: 23-29. doi:10.1192/bjp.bp.108.061424

Author Hamshere, M. L.
Green, E. K.
Jones, I. R.
Moskvina, V.
Kirov, G.
Grozeva. D.
Nikolov, I.
Vukcevic, D.
Caesar, S.
Gordon-Smith, K.
Fraser, C.
Russell, E.
Breen, G.
St Clair, D.
Collier, D. A.
Young, A. H.
Ferrier, I. N.
Farmer, A.
McGuffin, P.
Wellcome Trust Case Control Consortium
Brown, M. A.
Bradbury, L.
Holmans P. A.
Owen, M. J.
O'Donovan, M. C.
Craddock, N.
Title Genetic utility of broadly bipolar schizoaffective disorder as a diagnostic concept
Journal name British Journal of Psychiatry   Check publisher's open access policy
ISSN 0007-1250
Publication date 2009-07
Year available 2009
Sub-type Article (original research)
DOI 10.1192/bjp.bp.108.061424
Volume 195
Issue 1
Start page 23
End page 29
Total pages 7
Editor Tyrer, P.
Place of publication United Kingdom
Publisher Royal College of Psychiatrists
Collection year 2010
Language eng
Formatted abstract
Background Psychiatric phenotypes are currently defined according to sets of descriptive criteria. Although many of these phenotypes are heritable, it would be useful to know whether any of the various diagnostic categories in current use identify cases that are particularly helpful for biological-genetic research.
Aims To use genome-wide genetic association data to explore the relative genetic utility of seven different descriptive operational diagnostic categories relevant to bipolar illness within a large UK case-control bipolar disorder sample.
Method We analysed our previously published Wellcome Trust Case Control Consortium (WTCCC) bipolar disorder genome-wide association data-set, comprising 1868 individuals with bipolar disorder and 2938 controls genotyped for 276122 single nucleotide polymorphisms (SNPs) that met stringent criteria for genotype quality. For each SNP we performed a test of association (bipolar disorder group v. control group) and used the number of associated independent SNPs statistically significant at P<0.00001 as a metric for the overall genetic signal in the sample. We next compared this metric with that obtained using each of seven diagnostic subsets of the group with bipolar disorder: Research Diagnostic Criteria (RDC): bipolar I disorder; manic disorder, bipolar II disorder; schizoaffective disorder, bipolar type, DSM-IV: bipolar I disorder; bipolar II disorder; schizoaffective disorder, bipolar type.
Results The RDC schizoaffective disorder, bipolar type (v. controls) stood out from the other diagnostic subsets as having a significant excess of independent association signals (P<0.003) compared with that expected in samples of the same size selected randomly from the total bipolar disorder group data-set. The strongest association in this subset of participants with bipolar disorder was at rs4818065 (P = 2.42 x 10-7). Biological systems implicated included gamma amniobutyric acid (GABA)A receptors. Genes having at least one associated polymorphism at P<10-4 included B3GALTS, A2BP1, GABRB1, AUTS2, BSN, PTPRG, GIRK2 and CDH12.
Conclusions Our findings show that individuals with broadly defined bipolar schizoaffective features have either a particularly strong genetic contribution or that, as a group, are genetically more homogeneous than the other phenotypes tested. The results point to the importance of using diagnostic approaches that recognise this group of individuals. Our approach can be applied to similar data-sets for other psychiatric and non-psychiatric phenotypes.
Q-Index Code C1
Q-Index Status Confirmed Code

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2010 Higher Education Research Data Collection
UQ Diamantina Institute Publications
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Created: Wed, 14 Apr 2010, 10:46:57 EST by Kylie Hengst on behalf of UQ Diamantina Institute