Do Low Serum UCH-L1 and TDP-43 Levels Indicate Disturbed Ubiquitin-Proteosome System in Autism Spectrum Disorder?

Abstract

The mechanism of ubiquitination-related abnormalities causing neural development problems is still unclear. We examined the association between autism and serum transactive response DNA-binding protein-43 (TDP-43) and ubiquitin c-terminal hydrolase-L1 (UCH-L1) levels, both of which are members of the ubiquitin-proteosome system. We measured serum levels of TDP-43 and UCH-L1 in 24 children with autism and 24 healthy children. Childhood Autism Rating Scale (CARS) was used to assess symptom severity at admission. The mean serum TDP-43 and UCH-L1 levels in children with autism spectrum disorder (ASD) were found to decrease compared to healthy controls (p<0.001, 506.21±780.97 ng/L and 1245.80±996.76 ng/L, respectively; 3.08±5.44 ng/mL and 8.64±6.67 ng/mL, respectively). A positive correlation between serum TDP-43 levels and UCH-L1 levels was found in the ASD group (r=0.947, n=24, p<0.001). The CARS score of children with ASD was 48.91 points (standard deviation [SD]: 5.82). Low serum levels of UCH-L1 and TDP-43 may reflect disturbed ubiquitination in autism.