An association study of bipolar mood disorder (type I) with the 5-HTTLPR serotonin transporter polymorphism in a human population isolate from Colombia

The short variant of a functional length polymorphism in the promoter regio n of the serotonin transporter has been associated with several behavioural and psychiatric traits, including bipolar mood disorder. The same short al lele has also been implicated as a modifier of the bipolar phenotype. Here we evaluate the etiologic/modifier role of this polymorphism in a case (N = 103)/ control (N = 112) sample for bipolar mood disorder (type I) collecte d from an isolated South American population. We did not detect an associat ion between bipolar disorder and the 5-HTT promoter polymorphism in this sa mple. However, an excess of the short allele was seen in younger cases and in cases with psychotic symptoms. When combined with data from the literatu re, the increased frequency of the short allele in patients with psychotic symptoms was statistically significant. (C) 2000 Elsevier Science Ireland L td. All rights reserved.