Baseline brain perfusion and the serotonin transporter promoter polymorphism.
BACKGROUND
The serotonin transporter length repeat polymorphism (5-HTTLPR) in the promoter region of the serotonin transporter gene (SLC6A4) has been associated in healthy subjects with changes in basal perfusion levels in the limbic system and ventral prefrontal areas, regions involved in the pathophysiology of depression and anxiety, suggesting the existence of a neurobiological trait predisposing to these disorders. We reassess the findings of an increased baseline perfusion in the amygdala and ventral prefrontal areas in healthy carriers of the risk genotype in a much larger sample than in previous studies.


METHODS
A cohort of 183 healthy European individuals underwent perfusion imaging with continuous arterial spin-labeling (CASL) while resting quietly in the scanner for 8 minutes. Participants were genotyped to assess the occurrence of the short allele and the Lg and La variants of the long repeat.


RESULTS
No association between the 5-HTTLPR polymorphism and baseline brain perfusion was detected in the regions of interest or elsewhere in the brain. In the amygdala, variability in baseline perfusion was explained in large part by global cerebral flow levels (between 50% and 55%), in minor part by sex (between 4% and 5%), but not by genotype (less than .5%). Power analyses showed that the study was of sufficient size to be informative.


CONCLUSIONS
The findings did not confirm the existence of a biological marker of the effect of 5-HTTLPR polymorphism in the amygdala or in the orbitofrontal cortex.
Viviani
Roberto
R
Department of Psychiatry and Psychotherapy III, University of Ulm, Germany. roberto.viviani@uni-ulm.de
Sim
Eun-Jin
EJ
Lo
Hanna
H
Beschoner
Petra
P
Osterfeld
Nadine
N
Maier
Christiane
C
Seeringer
Angela
A
Godoy
Ana Leonor
AL
Rosa
Araceli
A
Comas
David
D
Kirchheiner
Julia
J
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000098:blood supply*; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000235:genetics*; D015331:Cohort Studies; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D010477:Perfusion; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D044465:White People; D055815:Young Adult
D050486:Serotonin Plasma Membrane Transport Proteins