title: A novel study on amyloid β peptide 40, 42 and 40/42 ratio in Saudi autistics.
abstract: OBJECTIVE
  We examined whether plasma concentrations of amyloid beta (Aβ) as protein derivatives play a central role in the etiology of autistic features.
  
  
  METHODS
  Concentrations of human Aβ (1-42), Aβ (1-40), and Aβ (40/42) in the plasma of 52 autistic children (aged 3-16 years) and 36 age-matched control subjects were determined by using the ELISA technique and were compared.
  
  
  RESULTS
  Compared to control subjects, autistic children exhibited significantly lower concentrations of both Aβ (1-40) and Aβ (1-42) and lower Aβ (40/42) concentration ratio. Receiver operating characteristics curve (ROC) analysis showed that these measurements of Aβ peptides showed high specificity and sensitivity in distinguishing autistic children from control subjects.
  
  
  CONCLUSIONS
  Lower concentrations of Aβ (1-42) and Aβ (1-40) were attributed to loss of Aβ equilibrium between the brain and blood, an imbalance that may lead to failure to draw Aβ from the brain and/or impairment of β- and γ- secretase's concentration or kinetics as enzymes involving in Aβ production.
authors.affiliation: Department of Physiology, Faculty of Medicine, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Laila Y
authors.initials: LY
authors.lastname: Al-Ayadhi
authors.forename: Abir G
authors.initials: AG
authors.lastname: Ben Bacha
authors.forename: Malak
authors.initials: M
authors.lastname: Kotb
authors.forename: Afaf K
authors.initials: AK
authors.lastname: El-Ansary
mesh_terms: D000293:Adolescent; D016229:Amyloid beta-Peptides / Q000097:blood*; D019540:Area Under Curve; D001321:Autistic Disorder / Q000097:blood* / Q000523:psychology; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003627:Data Interpretation, Statistical; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D018384:Oxidative Stress / Q000502:physiology; D010446:Peptide Fragments / Q000097:blood; D012372:ROC Curve; D012529:Saudi Arabia
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42)