Increased Serum Zonulin Levels as an Intestinal Permeability Marker in Autistic Subjects.

Objective: To evaluate the serum levels of zonulin, which regulates tight junctions between enterocytes and is a physiological modulator controlling intestinal permeability, in patients with autism spectrum disorders (ASDs).

Study Design: Serum zonulin levels were determined in 32 patients with ASD and 33 healthy controls using an enzyme-linked immunosorbent assay. The severity of ASD symptoms was assessed with the Childhood Autism Rating Scale.

Results: Serum zonulin levels were significantly higher in the patients with ASD (122.3 ± 98.46 ng/mL) compared with the healthy controls (41.89 ± 45.83 ng/mL). There was a positive correlation between zonulin levels and Childhood Autism Rating Scale score when all subjects were assessed (r = 0.523; P < .001).

Conclusions: This study suggests that zonulin, which regulates intestinal permeability, plays a role in the development of symptoms of ASD.