Estimation of Plasma Concentration of L-Carnosine and its Correlation with Core Symptoms of Autism Spectrum Disorder Children: A Pilot Clinical Trial

Background: Literature indicates that L-carnosine may be deficient in autism spectrum disorder (ASD) children. The aim of the present study was to estimate the level of L-carnosine in plasma and correlate it with the Autism Treatment Evaluation Checklist (ATEC) and Childhood Autism Rating Scale 2nd Edition, Standard Version (CARS2-ST) scores. To measure L-carnosine level, a bio-analytical method was developed using reverse phase high- liquid chromatography and validated as per International Conference on Harmonization guidelines. Method: Children were supplemented with L-carnosine (10–15 mg/kg) along with standard care therapies for 2 months. Before and after supplementation, scores on the ATEC, CARS2-ST, BEARS sleep screening tool, 6-item Gastrointestinal Severity Index, and Parental Stress Scale were evaluated, and L-carnosine was measured at the end of the trial. Results: The calibration curve was linear in the range of 100–600 ng/mL (R² = 0.998). The level of L-carnosine quantified was 33.7 ± 0.2 ng/mL. There was no significant difference found in any of the outcome measures (p > 0.05). Conclusions: Despite the fact that L-carnosine is detectable in the blood, it was found to be ineffective in the management of ASD in children. Clinical Trial Registration: The study was registered in the Clinical Trial Registry-India, registration number: CTRI/2019/07/020102.