[Presence of DRD4/7R and DAT1/10R allele in Chilean family members with attention deficit hyperactivity disorder].
BACKGROUND
Genes for dopamine receptor DRD4 and dopamine transporter DAT1 have been implicated in attention deficit with hyperactivity disorder (ADHD). However, the findings are not conclusive. More studies in populations with different genetic backgrounds may contribute to solve the discrepancies observed.


OBJECTIVE
To test the hypothesis that affected members of Chilean families exhibit higher frequencies of the DRD4/7R and DAT1/10R alleles then their healthy sibs.


METHODS
The parents of 51 children belonging to families of the Metropolitan Region of Chile, were approached to obtain clinical histories and blood samples, after the signature of a written informed consent. ADHD was diagnosed according to DSM-IV criteria, ancd intellectual coefficient was tested using the WISC-R test. Genomic DNA was extracted from lymphocytes and amplified by PCR.


RESULTS
The 7R allele was identified in 13 out of 26 subjects diagnosed as ADHD and in 6 of 25 healthy sibs (p < 0.05). Parents with a history of ADHD, were conmpared with their healthy counterparts, exhibiting an identical tendency, that did not reach statistical significance. No significant differences in the frequencies of DAT1/10R alleles, were observed between cases and controls or their parents.


CONCLUSIONS
Our results showed that ADHD in Chilean families is associated with the presence of DRD4/7R allele.
Carrasco
Ximena
X
Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago.
Rothhammer
Paula
P
Moraga
Mauricio
M
Henríquez
Hugo
H
Aboitiz
Francisco
F
Rothhammer
Francisco
F
D000293:Adolescent; D000483:Alleles; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D002677:Chile; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D005787:Gene Frequency / Q000235:genetics*; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D026901:Membrane Transport Proteins / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000235:genetics*; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D050638:Receptors, Dopamine D4
C493599:DRD4 protein, human; D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D017448:Receptors, Dopamine D2; C493214:SLC6A3 protein, human; D050638:Receptors, Dopamine D4