ASSOCIATION ANALYSIS OF THE CATECHOL O-METHYLTRANSFERASE GENE AND BIPOLAR AFFECTIVE-DISORDER

Objective: Catechol O-methyltransferase (COMT) is an enzyme that inact ivates catecholamines. Two common COMT alleles determine high and low activity of the enzyme. Previous studies using biochemical methods fou nd lower enzyme activity in patients with major depression and bipolar disorder in comparison with control values, suggesting that a dysfunc tion in catecholamine metabolism may be related to the etiology of dep ression. Method: The authors studied two recently described DNA polymo rphisms at the COMT gene (a silent C256G mutation and a structural mut ation, Val-108-Met) in 88 patients with bipolar disorder and in 113 he althy comparison subjects, all of Spanish origin. Results: The frequen cy of the C256 allele was 0.58 in the patients and 0.54 in the compari son subjects. The frequency of the Val108 variant was 0.57 for both th e patients and the comparison subjects. No allelic or genotypic associ ations were observed. Conclusions: The lack of association suggests th at the COMT gene is not a major risk factor for bipolar disorder.