Association of Rigid-Compulsive Behavior with Functional Constipation in Autism Spectrum Disorder

Behavioral Phenotype of ASD Preschoolers with Gastrointestinal Symptoms or Food Selectivity

This study investigated the prevalence and type of gastrointestinal (GI) and food selectivity (FS) symptoms in 163 preschoolers with ASD, and their possible links with core ASD features and emotional/behavioural problems. 40.5% of children with ASD had at least one severe GI symptom or FS. Preschoolers with and without GI symptoms and with and without FS were significantly different on several emotional/behavioural problems and restrictive/repetitive behaviours, whereas they did not differ significantly on performance IQ and autistic severity. The GI plus FS group presented with Sleep Problems, Self-injurious Behaviors and Anxiety Problems. Results indicated the need for early identification of GI disturbances and FS in order to design tailored intervention for these symptoms frequently associated to challenging behaviours in ASD.

Serotonin as a link between the gut-brain-microbiome axis in autism spectrum disorders

Autism-spectrum disorder (ASD) is a neurodevelopmental disorder characterized by persistent deficits in social communication and repetitive patterns of behavior. ASD is, however, often associated with medical comorbidities and gastrointestinal (GI) dysfunction is among the most common. Studies have demonstrated a correlation between GI dysfunction and the degree of social impairment in ASD. The etiology of GI abnormalities in ASD is unclear, though the association between GI dysfunction and ASD-associated behaviors suggest that overlapping developmental defects in the brain and the intestine and/or a defect in communication between the enteric and central nervous systems (ENS and CNS, respectively), known as the gut-brain axis, could be responsible for the observed phenotypes. Brain-gut abnormalities have been increasingly implicated in several disease processes, including ASD. As a critical modulator of ENS and CNS development and function, serotonin may be a nexus for the gut-brain axis in ASD. This paper reviews the role of serotonin in ASD from the perspective of the ENS. A murine model that has been demonstrated to possess brain, behavioral and GI abnormalities mimicking those seen in ASD harbors the most common serotonin transporter (SERT) based mutation (SERT Ala56) found in children with ASD. Discussion of the gut-brain manifestations in the SERT Ala56 mice, and their correction with developmental administration of a 5-HT₄ agonist, are also addressed in conjunction with other future directions for diagnosis and treatment.