title: Novel 5-HTTLPR allele associates with higher serotonin transporter binding in putamen: a [(11)C] DASB positron emission tomography study.
abstract: BACKGROUND
  The serotonin transporter (5-HTT)-linked polymorphic region (5-HTTLPR) has two frequent alleles, designated long (L), and short (S). The S allele is associated with lower levels of 5-HTT mRNA and lower 5-HTT expression in human cell lines. A functional single nucleotide variant was detected within L, designated L(A) and L(G). Only L(A) is associated with high levels of in vitro 5-HTT expression, whereas L(G) is low expressing and more similar to S. We examined the possible influence of the long (A/G) variant on 5-HTT density in the living human brain using 3-(11)C-amino-4-(2-dimethylaminomethylphenyl-sulfanyl) benzonitrile ([(11)C]DASB) positron emission tomography.
  
  
  METHODS
  The 5-HTT binding potential (5-HTT BP), an index of 5-HTT density, was found in 43 healthy subjects genotyped for 5-HTTLPR long (A/G), and in an ethnically homogenous subsample of 30 Caucasian-Canadians.
  
  
  RESULTS
  The L(A)/L(A) was associated with higher 5-HTT BP in putamen (p = .026, not corrected). This association became stronger in the Caucasian subsample (p = .004) and was significant even after correcting for multiple comparisons.
  
  
  CONCLUSIONS
  The 5-HTTLPR long (A/G) polymorphism influences 5-HTT density leading to higher putamen 5-HTT BP in healthy L(A)/L(A) carriers of Caucasian ancestry. This finding extends the role of this polymorphism from in vitro reports of higher 5-HTT expression with the L(A)/L(A) genotype into in vivo brains of healthy human subjects.
authors.affiliation: Vivian M Rakoff Positron Emission Tomography Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada.
authors.forename: Nicole
authors.initials: N
authors.lastname: Praschak-Rieder
authors.forename: James
authors.initials: J
authors.lastname: Kennedy
authors.forename: Alan A
authors.initials: AA
authors.lastname: Wilson
authors.forename: Douglas
authors.initials: D
authors.lastname: Hussey
authors.forename: Anahita
authors.initials: A
authors.lastname: Boovariwala
authors.forename: Matthaeus
authors.initials: M
authors.lastname: Willeit
authors.forename: Nathalie
authors.initials: N
authors.lastname: Ginovart
authors.forename: Subi
authors.initials: S
authors.lastname: Tharmalingam
authors.forename: Mario
authors.initials: M
authors.lastname: Masellis
authors.forename: Sylvain
authors.initials: S
authors.lastname: Houle
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Meyer
mesh_terms: D000483:Alleles; D000814:Aniline Compounds / Q000378:metabolism; D002250:Carbon Radioisotopes / Q000378:metabolism; D006801:Humans; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D049268:Positron-Emission Tomography; D011699:Putamen / Q000000981:diagnostic imaging / Q000378:metabolism*; D019275:Radiopharmaceuticals / Q000378:metabolism; D012016:Reference Values; D012701:Serotonin / Q000378:metabolism; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D013440:Sulfides / Q000378:metabolism; D044465:White People
chemical_list: C412822:3-amino-4-(2-dimethylaminomethylphenylsulfanyl)benzonitrile; D000814:Aniline Compounds; D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D050486:Serotonin Plasma Membrane Transport Proteins; D013440:Sulfides; D012701:Serotonin