Evidence of an association between 10/10 genotype of DAT1 and endophenotypes of attention deficit/hyperactivity disorder.
BACKGROUND
Genetic variance of attention deficit-hyperactivity disorder (ADHD) is a strong determinant of this disorder. The 40 base pairs (bp) variable number tandem repeat (VNTR) located in the 3' untranslated region (UTR) of DAT1 gene increases the expression of the dopamine transporter. Therefore, DAT1 has been associated with susceptibility to ADHD.


OBJECTIVE
To determine the association between the VNTR of DAT1 and the phenotype of ADHD or its endophenotypes in a sample of children aged between 6 and 15 years from Bogotá.


METHODS
We selected 73 patients with ADHD and 54 controls. WISC test was applied in all subjects and executive functions were assessed. The VNTR of DAT1 was polymerase chain reaction-amplified. Data regarding population genetics and statistical analysis were obtained. Correlation and association tests between genotype and neuropsychological testing were performed.


RESULTS
The DAT1 polymorphism was not associated with ADHD (P=.85). Nevertheless, the 10/10 genotype was found to be correlated with the processing speed index (P<.05). In the hyperactivity subtype, there was a genotypic correlation with some subtests of executive function (cognitive flexibility) (P≤.01). In the combined subtype, the 10/10 genotype was associated with verbal comprehension index of WISC (P<.05).


CONCLUSIONS
A correlation was found between DAT1 VNTR and the subtest "processing speed index" of WISC and the subtest "cognitive flexibility" of executive functions. To our knowledge, this is the first report to assess DAT1 gene in a Colombian population.
Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia.
J A
JA
Agudelo
Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia.
J M
JM
Gálvez
Unidad de Genética, Grupo de Investigación GENIUROS, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia.
D J
DJ
Fonseca
Unidad de Genética, Grupo de Investigación GENIUROS, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia.
H E
HE
Mateus
Unidad de Neurociencias, Grupo de Investigación en Neurociencias NEUROS, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia.
C
C
Talero-Gutiérrez
Grupo de Investigación en Neurociencias NEUROS, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia. Electronic address: alberto.velez@urosario.edu.co.
A
A
Velez-Van-Meerbeke
D020413:3' Untranslated Regions / Q000235:genetics; D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000235:genetics*; D002648:Child; D003105:Colombia; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D058068:Endophenotypes; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D018598:Minisatellite Repeats / Q000235:genetics; D009483:Neuropsychological Tests; D011110:Polymorphism, Genetic
D020413:3' Untranslated Regions; D050483:Dopamine Plasma Membrane Transport Proteins; C493214:SLC6A3 protein, human
Attention deficit-hyperactivity disorder; DAT1; Endofenotipo; Endophenotype; Executive function; Función ejecutiva; Genotipo; Genotype; Repetición en tándem en número variable; Trastorno por déficit de atención e hiperactividad; Variable number tandem repeats