Genetic mutations and synaptic dysfunctions in social interaction disorders: insights from invertebrate models to humans.

Abnormal social interactions are key features of various neurodevelopmental and neuropsychiatric disorders, including autism, attention-deficit/hyperactivity disorder, and schizophrenia. Social interaction behaviours are highly conserved and have evolved across species. Studying social behaviours is crucial as it determines an organism's survival, development, and reproduction. Research over the years has demonstrated how genetic mutations influence synaptic architecture and function, revealing their contributions to these social abnormalities. Furthermore, specific genes, known as cell adhesion molecules (CAM), play important roles in the formation, maturation, and functioning of the synapses, and mutations in these genes alter normal synaptic formation and functioning, consequently disrupting behavioural outcomes. In biological systems, normal synaptogenesis has functional implications for social behaviours necessary for social bonding and cooperation. This review integrates findings from studies across various model organisms-including the C. elegans, Drosophila melanogaster, Zebrafish, and rodents- to elucidate how alterations in synaptic function disrupt social interaction. We extensively discuss how mutations in CAM genes alter key conserved synaptic pathways, leading to neurochemical alterations that contribute to social deficits common in neurodevelopmental disorders, as well as therapeutic strategies inspired by animal studies, including the use of drugs and gene therapies in the management and treatment of the symptoms observed in social interaction disorders.