title: Serum BDNF levels in unaffected first-degree relatives of patients with bipolar disorder.
abstract: OBJECTIVE
  Unaffected relatives of bipolar disorder (BD) patients have been investigated for the identification of endophenotypes in an attempt to further elucidate the pathophysiology of the disease. Brain-derived neurotrophic factor (BDNF) is considered to be implicated in the pathophysiology of BD, but its role as an endophenotype has been poorly studied. We investigated abnormal serum BDNF levels in BD patients, in their unaffected relatives, and in healthy controls.
  
  
  METHODS
  BDNF levels were obtained from 25 DSM-IV bipolar I disorder patients, 23 unaffected relatives, and 27 healthy controls. All BD patients were in remission. The unaffected subjects were first-degree relatives of the proband who had no lifetime DSM-IV diagnosis of axis I disorder. BDNF serum levels were determined by sandwich ELISA using monoclonal BDNF-specific antibodies.
  
  
  RESULTS
  There were no statistical differences in BDNF levels among BD patients, relatives, and healthy controls.
  
  
  CONCLUSIONS
  Serum BDNF levels may not indicate high genetic risk for BD, possibly acting as state markers rather than trait markers of the disease.
authors: Programa de Transtorno Bipolar, Departamento de Psiquiatria, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brazil.|Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
authors: Fabiano G
authors: FG
authors: Nery
authors: Programa de Transtorno Bipolar, Departamento de Psiquiatria, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brazil.
authors: Alexandre D
authors: AD
authors: Gigante
authors: Programa de Transtorno Bipolar, Departamento de Psiquiatria, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brazil.
authors: Jose A
authors: JA
authors: Amaral
authors: Programa de Transtorno Bipolar, Departamento de Psiquiatria, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brazil.
authors: Francy B
authors: FB
authors: Fernandes
authors: Programa de Transtorno Bipolar, Departamento de Psiquiatria, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brazil.
authors: Mariangeles
authors: M
authors: Berutti
authors: Programa de Transtorno Bipolar, Departamento de Psiquiatria, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brazil.
authors: Karla M
authors: KM
authors: Almeida
authors: Laboratório de Psiquiatria Molecular, Centro de Pesquisas Experimentais, Hospital de Clínicas de Porto Alegre (HCPA), Instituto Nacional de Ciência e Tecnologia - Medicina Translacional (INCT-TM), Porto Alegre, RS, Brazil.
authors: Laura
authors: L
authors: Stertz
authors: Laboratório de Psiquiatria Molecular, Centro de Pesquisas Experimentais, Hospital de Clínicas de Porto Alegre (HCPA), Instituto Nacional de Ciência e Tecnologia - Medicina Translacional (INCT-TM), Porto Alegre, RS, Brazil.|Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors: Giovana
authors: G
authors: Bristot
authors: Laboratório de Psiquiatria Molecular, Centro de Pesquisas Experimentais, Hospital de Clínicas de Porto Alegre (HCPA), Instituto Nacional de Ciência e Tecnologia - Medicina Translacional (INCT-TM), Porto Alegre, RS, Brazil.|Programa de Pós-Graduação em Medicina, Psiquiatria, UFRGS, Porto Alegre, RS, Brazil.
authors: Flavio
authors: F
authors: Kapczinski
authors: Programa de Transtorno Bipolar, Departamento de Psiquiatria, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brazil.
authors: Beny
authors: B
authors: Lafer
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D001714:Bipolar Disorder / Q000097:blood* / Q000235:genetics; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D016022:Case-Control Studies; D058068:Endophenotypes / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005190:Family; D005260:Female; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales; D012016:Reference Values; D012307:Risk Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D019208:Brain-Derived Neurotrophic Factor