Study Report

Reference	Gawlik, M.,2010 PMID: 20667145
Citation	Gawlik, M., I. Wehner, et al. (2010). "The DAOA/G30 locus and affective disorders: haplotype based association study in a polydiagnostic approach." BMC Psychiatry 10: 59.
Disease Type	Bipolar Disorder & Major Depressive Disorder
Study Design	case-control
Study Type	Candidate-gene association study
Sample Size	129 patients with recurrent unipolar depression,119 patients with bipolar affective disorder and 188 control subjests
SNP/Region/Marker Size	7 SNPs
Predominant Ethnicity	Caucasian
Population	German
Gender	62% male for patients with affective disorders and 59% male for volunteer control subjects
Age Group	Adults : Mean age(SD)(year):42.7 (16.1) for patients with recurrent unipolar depression,35.9 (12.8) for patients with bipolar affective disorder and 30.2 (10.7) for control subjests

Sample Diagnosis	ICD-10
Sample Status	Cases were recruited from the Department of Psychiatry, Psychosomatics and Psychotherapy at of the University of Wurzburg. The sample encompassed 248 cases with affective disorders with a mean age of 48.1 years (15.7 SD) at recruitment. Diagnosis of recurrent unipolar depression with 'somatic syndrome' (ICD10 F33.11-F33.3), was made in 129 cases and of bipolar affective disorder in 119 cases. In addition, cases had to fulfil diagnostic criteria of monopolar depression (n = 57) and manic depression (n = 191) according to Leonhard's nosology. Diagnosis in differentiated psychopathology was made by repeated personal examinations of experienced psychiatrists (BJ, GS). The 188 volunteer control subjects were recruited from the blood donor centre at the University of Wurzburg. The preponderance of males in both samples avoided gender distortion in comparison of cases and controls. All subjects were unrelated and of German Caucasian descent.
Technique	PCR and sequencing
Statistical Method	Armitage's trend test was used to compare genotype distributions between cases and controls.
Result Summary	There was significant variation in the frequency of the HT2CR ser23 allele among the 10 population groups included in the sample (from 24.6% in Greek control subjects to 9.2% in Scots, chi(2) = 20.9, df 9, P = 0.01). Logistic regression analysis demonstrated that over and above this inter-population variability, there was a significant excess of HT2CR ser23 allele carriers in patients compared to normal controls that was demonstrable for both the MDD (chi(2) = 7.34, df 1, P = 0.006) and BP (chi(2) = 5.45, df 1, P = 0.02) patients. These findings support a possible role for genetically based structural variation in 5-HT2C receptors in the pathogenesis of major affective disorder.