title: Candidate gene-based association study of antipsychotic-induced movement disorders in long-stay psychiatric patients: a prospective study.
abstract: OBJECTIVE
  Four types of antipsychotic-induced movement disorders: tardive dyskinesia (TD), parkinsonism, akathisia and tardive dystonia, subtypes of TD (orofacial and limb truncal dyskinesia), subtypes of parkinsonism (rest tremor, rigidity, and bradykinesia), as well as a principal-factor of the movement disorders and their subtypes, were examined for association with variation in 10 candidate genes (PPP1R1B, BDNF, DRD3, DRD2, HTR2A, HTR2C, COMT, MnSOD, CYP1A2, and RGS2).
  
  
  METHODS
  Naturalistic study of 168 white long-stay patients with chronic mental illness requiring long-term antipsychotic treatment, examined by the same rater at least two times over a 4-year period, with a mean follow-up time of 1.1 years, with validated scales for TD, parkinsonism, akathisia, and tardive dystonia. The authors genotyped 31 SNPs, associated with movement disorders or schizophrenia in previous studies. Genotype and allele frequency comparisons were performed with multiple regression methods for continuous movement disorders.
  
  
  RESULTS
  VARIOUS SNPS REACHED NOMINAL SIGNIFICANCE: TD and orofacial dyskinesia with rs6265 and rs988748, limb truncal dyskinesia with rs6314, rest tremor with rs6275, rigidity with rs6265 and rs4680, bradykinesia with rs4795390, akathisia with rs4680, tardive dystonia with rs1799732, rs4880 and rs1152746. After controlling for multiple testing, no significant results remained.
  
  
  CONCLUSIONS
  The findings suggest that selected SNPs are not associated with a susceptibility to movement disorders. However, as the sample size was small and previous studies show inconsistent results, definite conclusions cannot be made. Replication is needed in larger study samples, preferably in longitudinal studies which take the fluctuating course of movement disorders and gene-environment interactions into account.
authors.affiliation: Psychiatric Centre GGZ Centraal, Amersfoort, The Netherlands. robertobakker@gmail.com
authors.forename: P Roberto
authors.initials: PR
authors.lastname: Bakker
authors.forename: Egbert
authors.initials: E
authors.lastname: Bakker
authors.forename: Najaf
authors.initials: N
authors.lastname: Amin
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: van Duijn
authors.forename: Jim
authors.initials: J
authors.lastname: van Os
authors.forename: Peter N
authors.initials: PN
authors.lastname: van Harten
mesh_terms: D014150:Antipsychotic Agents / Q000009:adverse effects*; D006801:Humans; D007902:Length of Stay; D001523:Mental Disorders / Q000188:drug therapy* / Q000235:genetics; D009069:Movement Disorders / Q000209:etiology*; D020641:Polymorphism, Single Nucleotide; D011446:Prospective Studies
chemical_list: D014150:Antipsychotic Agents