Relation of shyness in grade school children to the genotype for the long form of the serotonin transporter promoter region polymorphism.
OBJECTIVE
Studies have shown that genetic factors are significant in predisposing individuals to shyness and social phobia. Toward further elucidating the genetic structure of shyness, the authors examined four functional polymorphisms that make biological sense for contributing to the development of this phenotype: serotonin transporter promoter region 44 base pair insertion/deletion (5-HTTLPR), dopamine D(4) receptor exon III repeat (DRD4), catechol O-methyltransferase (COMT), and monoamine oxidase A promoter region repeat (MAO(A)).


METHODS
The authors assessed shyness after recruitment of a nonclinical sample (N=118, unscreened second-grade children) using a composite scale derived from questionnaires administered to the children, parents, and teachers. DNA from buccal smears successfully obtained from 98 children was genotyped by polymerase chain reaction methods for the 5-HTTLPR, DRD4, COMT, and MAO(A) polymorphisms.


RESULTS
Significant correlations were observed for parents', teachers', and children's ratings of shyness, and Cronbach's alpha reliability was high for all three scales. A significant association was observed between the long 5-HTTLPR polymorphism and shyness, both by the functional classification of Lesch as well as by consideration of all three genotypes. No significant association was observed for the DRD4, COMT, or MAO(A) polymorphisms.


CONCLUSIONS
This study provisionally identifies a common genetic polymorphism, 5-HTTLPR, that modestly (effect size=7%) contributed to greater shyness scores in a nonclinical group of second-grade students. These first findings may be relevant to previous reports that have shown an association between the 5-HTTLPR long form and obsessive-compulsive disorder and autism.
Arbelle
Shoshana
S
Unit for Child Psychiatry, Soroka Hospital, Beer Sheva, Israel.
Benjamin
Jonathan
J
Golin
Moshe
M
Kremer
Ilana
I
Belmaker
Robert H
RH
Ebstein
Richard P
RP
D000328:Adult; D000367:Age Factors; D001008:Anxiety Disorders / Q000209:etiology / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics*; D002394:Catechol O-Methyltransferase / Q000235:genetics; D002648:Child; D002652:Child Behavior / Q000523:psychology*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D026901:Membrane Transport Proteins; D008995:Monoamine Oxidase / Q000235:genetics; D009419:Nerve Tissue Proteins; D010290:Parents / Q000523:psychology*; D010641:Phenotype; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D017448:Receptors, Dopamine D2 / Q000235:genetics; D050638:Receptors, Dopamine D4; D012647:Self-Assessment; D050486:Serotonin Plasma Membrane Transport Proteins; D012792:Shyness; D011795:Surveys and Questionnaires; D013663:Teaching
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; D008995:Monoamine Oxidase; D002394:Catechol O-Methyltransferase