title: No significant association between response to methylphenidate and genes of the dopaminergic and serotonergic systems in a sample of Brazilian children with attention-deficit/hyperactivity disorder.
abstract: Few studies on pharmacogenetics of Attention-Deficit/Hyperactivity Disorder (ADHD) have been conducted. Most of them evaluated dopaminergic genes resulting in positive and negative findings. We assessed effects of polymorphisms in candidate dopaminergic (DRD4, DAT1) and serotonergic genes (HTR1B, HTR2A, and 5-HTT) on the response to treatment in 111 patients for whom methylphenidate (MPH) was prescribed. Outcome measures (Swanson, Nolan, and Pelham scale-version IV, Children Global Assessment Scale, Barkley's Stimulants Side Effects Rating Scale) were assessed at baseline and 1 month after the intervention. No significant association was detected between polymorphisms assessed and both response and side effects to MPH. Prospective multi-site controlled studies with larger sample sizes are needed in order to disentangle the role of candidate genes in response to ADHD treatment.
authors.affiliation: ADHD outpatient clinic, Child and Adolescent Psychiatric Division, Hospital de Clínicas de Porto Alegre, Federal University of Rio Grande do Sul, Rio Grande do Sul, Brazil.
authors.forename: Cristian Patrick
authors.initials: CP
authors.lastname: Zeni
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Guimarães
authors.forename: Guilherme V
authors.initials: GV
authors.lastname: Polanczyk
authors.forename: Julia P
authors.initials: JP
authors.lastname: Genro
authors.forename: Tatiana
authors.initials: T
authors.lastname: Roman
authors.forename: Mara H
authors.initials: MH
authors.lastname: Hutz
authors.forename: Luis Augusto
authors.initials: LA
authors.lastname: Rohde
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy* / Q000235:genetics*; D001938:Brazil; D000697:Central Nervous System Stimulants / Q000009:adverse effects / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000009:adverse effects / Q000627:therapeutic use*; D018598:Minisatellite Repeats; D011110:Polymorphism, Genetic; D044302:Receptor, Serotonin, 5-HT1B / Q000235:genetics; D044402:Receptor, Serotonin, 5-HT2A / Q000235:genetics; D050638:Receptors, Dopamine D4 / Q000235:genetics; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D016896:Treatment Outcome
chemical_list: D000697:Central Nervous System Stimulants; C493599:DRD4 protein, human; D050483:Dopamine Plasma Membrane Transport Proteins; C470302:HTR1B protein, human; D044302:Receptor, Serotonin, 5-HT1B; D044402:Receptor, Serotonin, 5-HT2A; C493214:SLC6A3 protein, human; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D050638:Receptors, Dopamine D4; D008774:Methylphenidate