A functional variant of the serotonin transporter gene in families with bipolar affective disorder

Background: The serotonin transporter protein (SERT) reuptakes serotonin from synapses and has been implied as the site of therapeutic action of many antidepressant drugs. SERT is one of the most relevant candidate genes for bipolar affective disorder. Recently a functionally important 44 basepair deletion in the regulatory region of the SERT gene was described. Association between this variant and affective disorder has been suggested. Methods: The present study analysed this variation and another variation in the SERT gene and nearby DNA markers in order to test for linkage between SERT and bipolar affective disorder in two Danish families. Results and conclusion: There was no evidence that variants in the SERT gene were a stronger dominant disease gene for the development of affective disorder in the families. The possibility of a recessive disease gene at or near SERT could not be excluded. Limitations: The present study cannot exclude if variations at or near the SERT gene were weak susceptibility genes or determine if they are important for other characteristics than presence or absence of disease. Clinical relevance: Further studies of the SERT gene in affective and other disorders, as well as in relation to treatment response to antidepressants are needed. (C) 1998 Elsevier Science B.V.