title: Genetic Variations in Attention Deficit Hyperactivity Disorder Subtypes and Treatment Resistant Cases.
abstract: OBJECTIVE
  ObjectiveaaWe evaluated the distribution of alpha-2A adrenergic receptor (ADRA2A) and catechol-o-methyltransferase (COMT) single nucleotide polymorphisms (SNPs) among ADHD subtypes and other homogeneous patient populations including treatment-resistant cases and patients with high symptom severity.
  
  
  METHODS
  Methodsaa121 ADHD patients aged 6-18 years were included in the study. Diagnosis and subtypes designation were confirmed using the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS) and symptoms were evaluated using the Conners' Parent (CPRS) and Teacher Rating Scales (CTRS). The response to methylphenidate was assessed objectively using the Clinical Global Impression-Severity Scale (CGI-S) and Global Assessment of Functioning Scale (GAS) as well as the Continuous Performance (CPT) and Trail Making tests (TMT-A, B). Patients were genotyped for ADRA2A (rs1800544) and COMT (rs4680) SNPs by PCR/RFLP and compared to a gender-matched control group.
  
  
  RESULTS
  Although there was no association of COMT (rs4680) SNP with symptoms or diagnosis, the ADRA2A polymorphism, low socioeconomic status (SES), and comorbid psychiatric diagnosis were all associated with poor response to methylphenidate in logistic regression analysis.
  
  
  CONCLUSIONS
  Clinicians may consider adjuvant strategies when these negative factors are present to increase the success of tailored ADHD treatments in the future.
authors.affiliation: Department of Child and Adolescent Psychiatry, Hacettepe University School of Medicine, Ankara, Turkey.
authors.forename: Dilek
authors.initials: D
authors.lastname: Unal
authors.affiliation: Department of Child and Adolescent Psychiatry, Hacettepe University School of Medicine, Ankara, Turkey.
authors.forename: Mehmet Fatih
authors.initials: MF
authors.lastname: Unal
authors.affiliation: Department of Medical Genetics, Hacettepe University School of Medicine, Ankara, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Alikasifoglu
authors.affiliation: Department of Medical Genetics, Hacettepe University School of Medicine, Ankara, Turkey.
authors.forename: Arda
authors.initials: A
authors.lastname: Cetinkaya
keywords: ADHD; ADRA2A; COMT; Genetics; Phenotype