title: Increased serum G72 protein levels in patients with schizophrenia: a potential candidate biomarker.
abstract: OBJECTIVE
  The product of the G72 gene is an activator of d-amino acid oxidase and has been suggested to play a role in the pathogenesis of schizophrenia. Increased G72 protein levels may be associated with disturbed glutamatergic transmission and increased reactive oxygen species. Only one pilot study by Lin et al. has investigated the potential role of serum G72 protein levels as a biomarker for schizophrenia. In this study, we aimed to compare serum G72 protein levels between patients with schizophrenia and healthy controls, and to retest the results of the previous pilot study. Materials and methods In total, 107 patients with a diagnosis of schizophrenia according to the inclusion and exclusion criteria and 60 age-sex-matched healthy controls were included in the study. The groups were compared regarding serum G72 protein levels.
  
  
  RESULTS
  The mean serum G72 protein values were 495.90±152.03 pg/ml in the schizophrenia group and 346.10±102.08 pg/ml in the healthy control group. The mean serum G72 protein level was significantly increased in the schizophrenia group compared with the healthy control group (t=-3.89, p<0.001). A receiver operating characteristics analysis was performed to compare the schizophrenia and healthy control groups. It was determined that the cut-off value was 141.51 pg/ml with a sensitivity of 0.991 and a specificity of 0.821.
  
  
  CONCLUSIONS
  We suggest that serum G72 protein levels may represent a candidate biomarker for schizophrenia and have confirmed the results of the previous preliminary study. Additional studies with larger sample sizes and the inclusion of first episode schizophrenia patients are required to clarify the reliability and validity of serum G72 protein levels as a biomarker for schizophrenia.
authors.affiliation: 1Department of Psychiatry,Yenimahalle Education and Research Hospital,Ankara,Turkey.
authors.forename: Esra Soydaş
authors.initials: ES
authors.lastname: Akyol
authors.affiliation: 2Department of Psychiatry, Faculty of Medicine,Namık Kemal University,Tekirdag,Turkey.
authors.forename: Yakup
authors.initials: Y
authors.lastname: Albayrak
authors.affiliation: 3Department of Biochemistry,Yenimahalle Education and Research Hospital,Ankara,Turkey.
authors.forename: Nurkan
authors.initials: N
authors.lastname: Aksoy
authors.affiliation: 4Department of Psychiatry, Faculty of Medicine,Çanakkale Onsekiz Mart University,Çanakkale,Turkey.
authors.forename: Başak
authors.initials: B
authors.lastname: Şahin
authors.affiliation: 2Department of Psychiatry, Faculty of Medicine,Namık Kemal University,Tekirdag,Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Beyazyüz
authors.affiliation: 5Department of Psychiatry, Faculty of Medicine,Akdeniz University,Antalya,Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Kuloğlu
authors.affiliation: 6Division of Clinical Neuroscience,Chiba University Center for Forensic Mental Health,Chiba,Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Hashimoto
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002352:Carrier Proteins / Q000097:blood*; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012559:Schizophrenia / Q000097:blood* / Q000175:diagnosis*
chemical_list: D015415:Biomarkers; D002352:Carrier Proteins; C475071:DAOA protein, human; D047908:Intracellular Signaling Peptides and Proteins
keywords: G72; biomarker; glutamate; schizophrenia