Characteristics of Cerebrospinal Fluid in Autism Spectrum Disorder - A Systematic Review

Abstract

AbstractAutism Spectrum Disorder (ASD) is a range of neurodevelopmental conditions characterized by impaired social interaction, learning, and restricted or repetitive behaviors. The underlying causes of ASD are still debated, but researchers have found many physiological traits to help understand the etiology of ASD. Some of the features that characterize people with ASD are immune markers (e.g. increased lymphocytes, cytokine levels), decreased neuropeptides like oxytocin and arginine vasopressin, folate deficiency, change in brain anatomy and physiology, and increased extra axial cerebrospinal fluid (CSF). CSF has a critical role in maintaining the homeostasis of the neuronal environment and has, therefore, been analyzed in multiple conditions that impact the central nervous system. The study of CSF is critical in understanding neurological disorders as its composition changes with the disorders, and these changes may indicate various disorder-related physiological mechanisms. For this systematic review, we searched the PubMed database for studies published between 1977 and 2023. We found 54 studies from 276 eligible for this review after manual screening. We took stock of the evidence supporting the hypothesis that ASD alters the properties and composition of CSF. We systematically report on the different attributes of CSF in the ASD population that could 1) be potential biomarkers, 2) assist in understanding the origins and progression of ASD, and 3) shed light on the aspects of the relationship between ASD and the immune system.