title: Lack of association of polymorphisms in six candidate genes in colombian adhd patients.
abstract: BACKGROUND
  Attention Deficit and Hyperactivity Disorder (ADHD) is a common childhood neuropsychiatric condition. The disorder has a multifactorial background, with heritability estimates of around 76%, suggesting an important role of genetic factors. Candidate genes include those related to dopaminergic (e.g. DRD4, DRD5, SLC6A3 and DBH)and serotoninergic (e.g.HTR1B and SLC6A4) pathways.
  
  
  OBJECTIVE
  To explore the association of common polymorphisms in six genes (DRD4, DRD5, SLC6A3, DBH, HTR1B and SLC6A4) and the susceptibility to ADHD in a Colombian sample population.
  
  
  METHODS
  trios and 152 healthy controls were recruited. Genotyping of the six polymorphisms was performed using described PCR-based protocols. A TDT analysis was used to test if there was preferential allelic transmission for any of the six polymorphisms. Additionally, a case-control analysis was performed to test for association of the serotoninergic (HTR1B and SLC6A4) polymorphisms with ADHD.
  
  
  RESULTS
  Through the TDT analysis there was no preferential allelic transmission for any of the studied variants. Case-control analysis did not show association.
  
  
  CONCLUSIONS
  This is the first study in Latin America to describe six polymorphisms in a group of patients with ADHD. There was no evidence of association for any of the studied polymorphic variants in this Colombian ADHD sample. Further research, with larger sample sizes and study of endophenotypes, is needed in this population to confirm and extend the results.
authors.affiliation: Research group Geniuros. School of Medicine and Health Sciences. Universidad del Rosario. Bogotá, Colombia;
authors.forename: Dora J
authors.initials: DJ
authors.lastname: Fonseca
authors.affiliation: Research group Geniuros. School of Medicine and Health Sciences. Universidad del Rosario. Bogotá, Colombia;
authors.forename: Heidi E
authors.initials: HE
authors.lastname: Mateus
authors.affiliation: Research group Geniuros. School of Medicine and Health Sciences. Universidad del Rosario. Bogotá, Colombia;
authors.forename: Jubby M
authors.initials: JM
authors.lastname: Gálvez
authors.affiliation: Laboratory of NeuroPsychiatric Genetics, Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño. Bogotá, Colombia;
authors.forename: Diego A
authors.initials: DA
authors.lastname: Forero
authors.affiliation: Neuroscience Research Group NEUROS. School of Medicine and Health Sciences. Universidad del Rosario. Bogotá, Colombia.
authors.forename: Claudia
authors.initials: C
authors.lastname: Talero-Gutierrez
authors.affiliation: Neuroscience Research Group NEUROS. School of Medicine and Health Sciences. Universidad del Rosario. Bogotá, Colombia.
authors.forename: Alberto
authors.initials: A
authors.lastname: Velez-van-Meerbeke
keywords: Association; Attention Deficit and Hyperactivity Disorder; Genes; Latin America; Transmission Disequilibrium Test