Investigation of the Relationship Between Prodynorphin Gene Polymorphisms and Sensory Differences in Children With Autism Spectrum Disorder.

BACKGROUND: Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by deficits in social communication and repetitive behaviours. Sensory processing abnormalities are now recognized as a core feature of ASD and have been extensively studied. While differences in sensory profiles between individuals with and without ASD are well established, the genetic underpinnings of sensory variability within the ASD population remain unclear. The opioid system is believed to play a role in processes such as social behaviours, pain, addiction, reward, mood, cognition and perception. This study aimed to investigate the relationship between ASD, sensory differences and prodynorphin (PDYN) gene polymorphisms.

METHODS: This was a case-control study that included 45 children aged 3 to 7 years diagnosed with ASD and 45 neurotypical children matched for age and gender. The parents of all participating children were administered the Sociodemographic Data Form, the Autism Behaviour Checklist and the Dunn Sensory Profile-Parent Questionnaire. The ASD clinical severity of the cases was assessed using the Childhood Autism Rating Scale. Venous blood samples were collected from all the children for the analysis of PDYN gene polymorphisms. Prodynorphin gene variants were genotyped using polymerase chain reaction-restriction fragment length polymorphism methods.

RESULTS: No significant differences were found between the ASD and control groups in terms of PDYN gene polymorphisms. While there were no differences in scores related to endurance and tone sensory processing, low endurance-tone and inactivity between the groups, all other subtest scores were significantly lower in the ASD group. In children with ASD, a significant difference was observed in the number of individuals showing atypical performance in the oral sensory processing and regulation of visual inputs influencing emotional responses and activity level subtests for the prodynorphin rs1022563 polymorphism.

CONCLUSIONS: Due to the preliminary nature of this investigation and the relatively small sample size, these findings should be interpreted with caution and require validation in larger cohorts. These preliminary findings suggest a potential modulatory role of PDYN gene variants in sensory processing characteristics among children with ASD. These novel findings warrant replication in larger cohorts to validate the influence of PDYN polymorphisms on sensory phenotypes and to further clarify their neurobiological relevance.