title: Dopamine transporter gene and response to methylphenidate in attention-deficit/hyperactivity disorder.
abstract: This study aims to evaluate whether a previously reported association between homozygosity for the 10-repeat allele of the dopamine transporter gene (10/10) and poor response to methylphenidate (MPH) would be replicated in a sample of Brazilian attention deficit/hyperactivity disorder (ADHD) boys. In a blind naturalistic study, 50 male ADHD youths were treated with MPH. Efficacy of the medication was measured by means of the 10-item Conners Abbreviated Rating Scale (ABRS), and the Children's Global Assessment Scale (CGAS). While 75% (15/20) of the youths without 10/10 genotype demonstrated an improvement higher than 50% in the ABRS scores with MPH, only 47% (14/30) of the subjects with 10/10 genotype achieved the same level of improvement with medication (one-tailed P = 0.04). In addition, the group without this genotype had significantly higher increase in the CGAS scores than the other group (one-tailed P < 0.01). Our findings support an association between homozygosity for the 10-repeat allele at dopamine transporter gene locus and poor response to MPH.
authors.affiliation: Department of Genetics, Federal University of Rio Grande do Sul, Brazil.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Roman
authors.forename: Claudia
authors.initials: C
authors.lastname: Szobot
authors.forename: Silvia
authors.initials: S
authors.lastname: Martins
authors.forename: Joseph
authors.initials: J
authors.lastname: Biederman
authors.forename: Luis A
authors.initials: LA
authors.lastname: Rohde
authors.forename: Mara H
authors.initials: MH
authors.lastname: Hutz
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy* / Q000235:genetics*; D001938:Brazil; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002648:Child; D004298:Dopamine / Q000235:genetics; D050483:Dopamine Plasma Membrane Transport Proteins; D004305:Dose-Response Relationship, Drug; D005838:Genotype; D006720:Homozygote; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins / Q000235:genetics*; D008774:Methylphenidate / Q000627:therapeutic use*; D009419:Nerve Tissue Proteins; D011110:Polymorphism, Genetic
chemical_list: D000697:Central Nervous System Stimulants; D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D008774:Methylphenidate; D004298:Dopamine