الفهرس 
Title pageOnly 14 pages are availabe for public view
 |  | from | 133 |  |  |
| | | from | 133 | | |
Abstract
Autism spectrum disorder (ASD) refers to a complex group of neurodevelopmental disorders characterized by deficits in social communication and language and gains in repetitive and restrictive behaviors and interests. characteristics must appear from early childhood before the age of two, even if these are not obvious until later in childhood. The prevalence of ASD has been steadily increasing over the past 20 years, due to increased awareness and advancing diagnoses.
ASD is a complex multifactorial disorder.Till now, there is no definitive diagnostic test to identify individuals with ASD. In the last decade, there have been huge findings concerning environmental, genetic, epigenetic, organic/immunological deficits, and biochemical burdens as suspected etiological and risk factors for ASD. One major component that appears highly impacted in ASD is Oxytocin (OXT).
Oxytocin, the brain’s most abundant neuropeptide, plays an important role in social salience and motivation. OXT regulates social behavior via direct modulation of neurons, regulation of neural network activity, and interaction with other neurotransmitter systems through the oxytocin receptor (OXTR). OXTR-mRNA expression is widespread and diffused throughout the brain, with specific areas displaying a particularly robust expression. Recent data suggested that altered plasma levels of OXT, as well as OXTR polymorphisms, have been associated with ASD.
The present study aimed to evaluate the association of ASD risk with the expression of OXTR mRNA and OXT concentration in a group of selected children with autism. (Krotkiewski et al., 1983; Hyman et al., 2020)
The study included thirty patients (25 males and 5 females) aged 3-12 years old diagnosed with non-syndromic Autism according to the criteria defined in Childhood Autism Rating Scale (CARS) and the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-V). All patients were referred to the Outpatient Clinic of Neuro-Rehabilitation & Learning Disabilities, Medical Research Center of Excellence, at the National Research Centre (NRC) from 2020 to 2021. A comparable group included 30 healthy children (24 males and 6 females) with matched ages and sex was selected and enrolled in the study as a normal control group.
The study results revealed that cases age was above 3 years old. The median of their age was 7 (range: from 4 – 11.6) years. Males constituted the majority of cases (83.3%). Positive consanguinity was found in 43.3% of the cases. The mean maternal and paternal age at the time of the cases’ birth was 33.3 ± 6.3 and 37.6 ± 7.2, respectively, but the maternal age in cases is statistically lower than the control. The onset of symptoms at the age of 1 to 2 years and 2 to 3 years was in 76.7% and 23.3% of the cases, respectively.
According to CARS scores, the ASD cases children were classified as: Mild ASD (CARS score: >33): 21 cases (70%), Moderate ASD (CARS score: 34-37): 9 cases (30%),Severe A.S.D. (CARS score : > 37): no cases found in the current study. With CARS score mean: 32.3±1.9, median: 32.5(28.5-39.5), With average scoring in all CARS characteristics. ASD cases distribution according to I.Q. reveals 26.7% of cases had IQ less than 70, 36.7% of cases with I.Q between 70-79 and 36.7% of cases with I.Q between 80-89. I.Q scoring mean: 75.6±8.9 with median: 78.5(56-88)
The concentrations of OXT in blood samples were measured using the Enzyme-Linked Immunosorbent assay (ELISA) method using human OXT-ELISA kits. Gene Expression level of the mRNA of the OXTR gene in the blood of the selected cases/controls was carried out using the Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) device (DNA Technology, Moscow, Russia) using Maxima SYBR Green qPCR master mix (2X) (Thermo Scientific, Thermo Fisher Scientific, Lithuania), based on comparative delta delta Ct method.
The OXT level in autistic cases was statistically significant lower than controls with a median of 87(53-268), and 177(62-231), respectively (P=0.0001). Also, the fold change of OXTR gene expression was statistically significant lower than controls with a median of 0.28 (.07- 5.5) and 1.39 (.01-67.03), respectively (P=0.012).
There was a significant correlation between the fold change of the OXTR gene expression and the OXT level (p=0.039) in autistic cases as they are significantly decreased related to each other. While this correlation was insignificant in the controls (p=0.055).