Examining the Potential Link Between Forkhead Box P1 and Severity and Social Impairment in Children with Autism Spectrum Disorder.

Background: Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by impaired social skills and communication. Forkhead box protein P1 (FOXP1) is involved in the development of the brain and the pathogenesis of ASD. However, the function of FOXP1 within the brain remains unclear. The aim of this case-control study was to evaluate whether FOXP1 could be used as a diagnostic biomarker for ASD. Method: Blood plasma was collected from children with ASD and age-matched controls. The enzyme-linked immunosorbent assay (ELISA) was used to determine the FOXP1 plasma levels in ASD and control groups. The behavioral and social impairments in children with ASD were assessed using the Childhood Autism Rating Scale (CARS) and the Social Responsiveness Scale (SRS). Spearman's correlation coefficient (r) was used to determine the correlation between different variables. Results: The plasma FOXP1 protein level was significantly decreased in children with ASD compared to the controls (p < 0.001). CARS showed significant differences between the mild-to-moderate and severe subgroups, while the SRS showed no significant difference between the two subgroups. Moreover, both the mild-to-moderate and severe subgroups exhibited a substantial drop in plasma FOXP1 compared to the controls. ASD children older than six years old also showed a significantly decreased FOXP1 level, compared to those aged six years or less. Furthermore, no significant correlation between the FOXP1 level, CARS, and SRS was observed. However, a negative correlation was found between age and FOXP1 plasma level. Conclusions: We suggest that plasma FOXP1 may act as a potential biomarker for the prognosis of ASD severity and social communication impairment. Further research with a larger sample size is needed to clarify these associations and help diagnose or understand the underlying mechanism of ASD.