The Association Between Branched-Chain Amino Acid Concentrations and the Risk of Autism Spectrum Disorder in Preschool-Aged Children

Abstract

Several studies have linked branched-chain amino acid (BCAA) metabolism disorders with autism spectrum disorder (ASD), but the results have been inconsistent. The purpose of this study was to explore the association between BCAA concentrations and the risk of ASD. A total of 313 participants were recruited from two tertiary referral hospitals from May 2018 to July 2021. Concentrations of BCAAs in dried blood spots were analyzed using liquid chromatography-tandem mass spectrometry-based analysis. Multivariate analyses and restricted cubic spline models were used to identify the association between BCAAs and the risk of ASD, and a nomogram was developed by using multivariate logistic regression and the risk was determined by receiver operating characteristic curve analysis and calibration curve analysis. Concentrations of total BCAA, valine, and leucine/isoleucine were higher in the ASD group, and all of them were positively and non-linearly associated with the risk of ASD even after adjusting for potential confounding factors such as age, gender, body mass index, and concentrations of BCAAs (P < 0.05). The nomogram integrating total BCAA and valine showed a good discriminant AUC value of 0.756 (95% CI 0.676-0.835). The model could yield net benefits across a reasonable range of risk thresholds. In the stratified analysis, the diagnostic ability of the model was more pronounced in children older than 3 years. We provide evidence that increased levels of BCAAs are associated with the risk of ASD, and the nomogram model of BCAAs presented here can serve as a marker for the early diagnosis of ASD.

Keywords: Autism spectrum disorders; Branched-chain amino acids; Early diagnosis; Nomogram; Preschool children.

Fig. 1

Comparison of BCAA levels between children with ASD and TD controls in different groups stratified by age, gender, and BMI

Fig. 2

Restricted cubic spline model of the odds ratios of ASD with BCAA levels in DBSs. The red line and red shadow represent adjusted odds ratios and 95% confidence intervals, respectively. The black dotted line represents odds ratios = 1.00. The risk estimates for ASD were adjusted to account for age, gender, BMI, and the levels of total BCAAs, Val, and Leu

Fig. 3

Nomogram for predicting the risk of ASD and model evaluation. A A nomogram was constructed based on two independent predictors, and the values of the included factors are marked on the corresponding axis. A vertical line was drawn from the value to the top lines to get the corresponding points. The points identified on the points scale for each variable were summed to obtain the probability of ASD. B ROC curves for evaluating the model’s discriminatory ability. C Calibration plot of the risk nomogram. The ideal outcome (dashed line), the observed outcome (fine dashed line), and the bias-corrected outcome (solid line) are depicted. D DCA for the risk nomogram. The y-axis shows the net benefit. The grey solid line represents the assumption that all patients had ASD. The blue solid line represents the assumption that none of the patients had ASD. The red solid line represents the risk nomogram

Fig. 4

The potential diagnostic value of BCAAs for ASD in the different groups stratified by age, gender, and BMI. Model: the nomogram model constructed with BCAAs

Fig. 5

Association of concentrations of BCAAs in DBSs with severity of ASD. A Multiple logistic regression analysis of the associations between concentrations of BCAAs and severity of ASD. Model 1, not adjusted. Model 2, adjusted for age, gender, and BMI. Model 3, adjusted for age, gender, BMI, and levels of total BCAAs, Val, and Leu. The blue dots represent the adjusted OR, and the horizontal lines represent the 95% CI. B Restricted cubic spline model of the odds ratios of severity of ASD with total BCAA levels in DBSs. The blue line and blue shadow represent adjusted odds ratios and 95% confidence intervals, respectively. The black dotted line represents odds ratios = 1.00