title: A study of blood serotonin and serotonin transporter promoter variant (5-HTTLPR) polymorphism in Egyptian autistic children.
abstract: BACKGROUND
  Autism spectrum disorder (ASD) is a complex, heterogeneous neurodevelopmental disorder with onset during early childhood. Most studies have reported an elevation in platelet serotonin in persons with autism. The serotonin (5-hydroxytryptamine; 5-HT) transporter in the brain uptakes 5-HT from extracellular spaces. It is also present in platelets, where it takes up 5-HT from plasma. Polymorphisms in serotonin transporter gene (SLC6A4) were frequently studied in many neuropsychiatric disorders.
  
  
  METHODS
  We have measured the plasma 5-HT levels in 20 autistic male children and 20 control male children by the enzyme-linked immunosorbent assay (ELISA) method. In addition, the SLC6A4 promoter region (5-HTTLPR) insertion/deletion (I/D) polymorphism was studied, using whole genomic DNA.
  
  
  RESULTS
  Plasma serotonin was significantly low in autistic children compared to control (P = 0.001), although correlation to severity of autism was not significant. The frequency of short (S) allele in autism cases was 10% and in the control group it was absent.
  
  
  CONCLUSIONS
  Our study demonstrated an increased prevalence of 5-HTTLPR S allele in autism subjects. Significantly decreased plasma serotonin was detected in autism subjects, with no significant relationship between 5-HTTLPR genotype and plasma 5-HT being evident.
authors.affiliation: Department of Research on Children with Special Needs, Medical Division National Research Centre, Cairo, Egypt.
authors.forename: Nagwa A
authors.initials: NA
authors.lastname: Meguid
authors.affiliation: Department of Research on Children with Special Needs, Medical Division National Research Centre, Cairo, Egypt.
authors.forename: Ola H
authors.initials: OH
authors.lastname: Gebril
authors.affiliation: Department of Research on Children with Special Needs, Medical Division National Research Centre, Cairo, Egypt.
authors.forename: Rehab O
authors.initials: RO
authors.lastname: Khalil
keywords: Gene promoter; platelet; reuptake; serotonin; synapses; transport