title: Serotonin transporter gene-linked polymorphic region: possible pharmacogenetic implications of rare variants.
abstract: A functional insertion/deletion (*l/*s) repeat polymorphism within the promoter region of the serotonin transporter (5-HTTLPR) has been described. An association between *l variant and a better and faster response to serotonin selective reuptake inhibitors in depressed patients was reported in Caucasians. The value of the explained variance due to the 5-HTTLPR, however, was 7% only, and different *l and *s variants were reported according to the nucleotide sequence of repeats. In this study, we investigated the antidepressant response to fluvoxamine in individuals carrying different *l and *s variants according to the Nakamura findings. Two hundred and twenty-eight patients affected by bipolar disorder and major depression were administered a daily dose of fluvoxamine up to 300 mg and evaluated at baseline and weekly thereafter until week 7, using the 21-item Hamilton Rating Scale for Depression. We found a marginally significant difference in genotype and allele (P=0.04, data not shown) distribution (*l and *s traditional variants) according to diagnosis (bipolar disorder vs. major depression). We confirmed a better and faster response in our depressed patients bearing the *l variant, but we also found significant differences in response among *l carriers according to the type of *l allele. In fact, 16F *l carriers showed only a partial response, while 16D *l carriers showed a marginally significantly better response than 16A *l allele carriers. These results, although very preliminary, can represent a further step toward a better understanding of the molecular genetics of antidepressant response.
authors.affiliation: Department of Psychiatry, San Raffaele Institute, Vita-Salute University, Milan, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Smeraldi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Serretti
authors.forename: Paola
authors.initials: P
authors.lastname: Artioli
authors.forename: Cristina
authors.initials: C
authors.lastname: Lorenzi
authors.forename: Marco
authors.initials: M
authors.lastname: Catalano
mesh_terms: D000328:Adult; D001483:Base Sequence; D001714:Bipolar Disorder / Q000235:genetics*; D004247:DNA / Q000097:blood / Q000235:genetics; D017931:DNA Primers; D003866:Depressive Disorder / Q000235:genetics*; D005260:Female; D016666:Fluvoxamine / Q000494:pharmacology; D005787:Gene Frequency; D006580:Genetic Carrier Screening; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology
chemical_list: D004247:DNA; D017931:DNA Primers; D016666:Fluvoxamine; D050486:Serotonin Plasma Membrane Transport Proteins; D017367:Selective Serotonin Reuptake Inhibitors