title: Brain-Derived Neurotrophic Factor Levels in Autism: A Systematic Review and Meta-Analysis.
abstract: Brain-derived neurotrophic factor (BDNF) plays an important role in activity-dependent synaptic plasticity. Altered blood BDNF levels have been frequently identified in people with autism spectrum disorders (ASD). There are however wide discrepancies in the evidence. Therefore, we performed the present systematic review and meta-analysis aimed at qualitative and quantitative synthesis of studies that measured blood BDNF levels in ASD and control subjects. Observational studies were identified through electronic database searching and also hand-searching of reference lists of relevant articles. A total of 183 papers were initially identified for review and eventually twenty studies were included in the meta-analysis. A meta-analysis of blood BDNF in 887 patients with ASD and 901 control subjects demonstrated significantly higher BDNF levels in ASD compared to controls with the SMD of 0.47 (95% CI 0.07-0.86, p = 0.02). In addition subgroup meta-analyses were performed based on the BDNF specimen. The present meta-analysis study led to conclusion that BDNF might play role in autism initiation/ propagation and therefore it can be considered as a possible biomarker of ASD.
authors.affiliation: Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.|MetaCognition Interest Group (MCIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran.
authors.forename: Amene
authors.initials: A
authors.lastname: Saghazadeh
authors.affiliation: Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran. rezaei_nima@tums.ac.ir.|Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. rezaei_nima@tums.ac.ir.|Systematic Review and Meta-analysis Expert Group (SRMEG), Universal Scientific Education and Research Network (USERN), Boston, MA, USA. rezaei_nima@tums.ac.ir.|Children's Medical Center Hospital, Dr. Qarib St, Keshavarz Blvd, Tehran, 14194, Iran. rezaei_nima@tums.ac.ir.
authors.forename: Nima
authors.initials: N
authors.lastname: Rezaei
mesh_terms: D000067877:Autism Spectrum Disorder / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male
chemical_list: D015415:Biomarkers; D019208:Brain-Derived Neurotrophic Factor; C579455:BDNF protein, human
keywords: Autism; Brain-derived neurotrophic factor; Meta-analysis; Neuroplasticity; Systematic review