title: Molecular genetics of the psychosis phenotype.
abstract: OBJECTIVE
  Relative to recent successes in elucidating the genetic mechanisms associated with complex diseases, including macular degeneration, diabetes mellitus, type 2, heart disease, and cancer, molecular genetic approaches to psychiatric illness have met with more limited success. While factors such as small allelic effects, allelic heterogeneity, and variation in population substructure have received considerable attention in attempt to explain the paucity of significant results in psychiatric genetics, significantly less focus has been directed toward phenotypic factors.
  
  
  METHODS
  Data derived from molecular genetic studies of the psychosis phenotype in patients with a range of psychiatric illnesses are reviewed.
  
  
  RESULTS
  Available data suggest that genes do not respect the boundaries of the current diagnostic system but may confer risk for symptom-based phenotypic variation that traverses those boundaries.
  
  
  CONCLUSIONS
  Molecular genetic studies offer convincing evidence for a relation between genetic variation and symptom-based phenotypic variation within psychiatric illness. These data may provide novel insights into the pathophysiology of schizophrenia and other related disorders. The exploration of relations between genetic variation and symptom variation that traverses traditional diagnostic boundaries may ultimately lead to more refined classification systems that more closely reflect the genetic etiology of psychiatric illness.
authors: Center for Psychiatric Neuroscience, Feinstein Institute for Medical Research, Manhasset, NY, USA. pderosse@lij.edu
authors: Pamela
authors: P
authors: DeRosse
authors: Anil K
authors: AK
authors: Malhotra
authors: Todd
authors: T
authors: Lencz
mesh_terms: D001714:Bipolar Disorder / Q000175:diagnosis / Q000235:genetics / Q000523:psychology; D002352:Carrier Proteins / Q000235:genetics; D002394:Catechol O-Methyltransferase / Q000235:genetics; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000235:genetics / Q000523:psychology; D003937:Diagnosis, Differential; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics / Q000523:psychology; D000074765:Dysbindin; D049029:Dystrophin-Associated Proteins; D056726:Genetic Association Studies; D008040:Genetic Linkage; D020022:Genetic Predisposition to Disease / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics; D005838:Genotype; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins / Q000235:genetics; D020890:Neuregulin-1 / Q000235:genetics; D010641:Phenotype; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics*; D012565:Schizophrenic Psychology
chemical_list: D002352:Carrier Proteins; C475071:DAOA protein, human; C412476:DISC1 protein, human; C432416:DTNBP1 protein, human; D000074765:Dysbindin; D049029:Dystrophin-Associated Proteins; D047908:Intracellular Signaling Peptides and Proteins; C094131:NRG1 protein, human; D009419:Nerve Tissue Proteins; D020890:Neuregulin-1; D002394:Catechol O-Methyltransferase