No interaction between serotonin transporter gene and dopamine receptor D4 gene in symptomatology of major psychoses.
Previously, we reported an association of the dopamine receptor D4 (DRD4) gene with delusional symptomatology of major psychoses. However, DRD4 variants accounted for only 2% of the phenotypic variance, indicating that contributions from other genes were probable. The serotonin transporter gene is a primary candidate in major psychoses, and a functional polymorphism in the upstream regulatory region of the serotonin transporter gene (5-HTTLPR) has recently been reported to be associated with a number of psychopathological conditions. In the present study we investigated the original cohort of subjects to evaluate the 5-HTTLPR possible influence on the psychopathology of major psychoses in interaction with DRD4. Four hundred and sixty-one inpatients affected by major psychoses were assessed by the Operational Criteria Checklist for Psychotic Illness (OPCRIT) and were also typed for the 5-HTTLPR and DRD4 variants using polymerase chain reaction techniques. Mania, depression, delusion, and disorganization were the four symptomatologic factors used as phenotype definition. 5-HTTLPR variants did not significantly influence the previously reported association of DRD4 with delusional symptoms. No interaction was observed on the other symptom factors. The serotonin transporter gene does not, therefore, interact with DRD4 in determining the symptomatology of major psychoses.
Serretti
A
A
Department of Neuropsychiatric Sciences, Istituto Scientifico H San Raffaele, University of Milan School of Medicine, Italy. serretti.alessandro@hsr.it
Cusin
C
C
Lattuada
E
E
Lilli
R
R
Lorenzi
C
C
Di Bella
D
D
Catalano
M
M
Smeraldi
E
E
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000483:Alleles; D001714:Bipolar Disorder / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D003866:Depressive Disorder / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D026901:Membrane Transport Proteins; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D010259:Paranoid Disorders / Q000235:genetics*; D010641:Phenotype; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D050638:Receptors, Dopamine D4; D012044:Regression Analysis; D012559:Schizophrenia / Q000235:genetics*; D050486:Serotonin Plasma Membrane Transport Proteins
D002352:Carrier Proteins; C493599:DRD4 protein, human; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D017448:Receptors, Dopamine D2; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D050638:Receptors, Dopamine D4