The genetic pathways involved in sensory hypersensitivity and related psychiatric disorders

Results

Sensory hypersensitivity and associated disorders, often called sensory processing disorder (SPD), involves an atypical increased sensitivity and an excessive reaction to sensory stimuli such as images, sounds, touch, smells, tastes, movements or internal bodily sensations. People with sensory hypersensitivity may find the daily sensory input overwhelming or even painful, resulting in strong emotional and behavioral responses. This phenomenon is commonly observed in a range of psychiatric and neurodevelopmental disorders, including autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), Tourette’s syndrome (TS), bipolar disorder, schizophrenia and mood disorders. The interaction between the genetic pathways governing the inhibitory/excitatory balance, neuromodulation, synaptic plasticity and immune interactions provides a complete framework for understanding the neurogenetic basis of sensory hypersensitivity in psychiatric conditions. Genetic alterations affecting the balance between excitatory (glutamatergic) and inhibitory (GABAergic) neurotransmission appear as central mechanisms underlying sensory hypersensitivity. Variants of the genes regulating the neuromodulation of serotonin and dopamine further influence sensory processing and emotional regulation. These pathways modulate the excitability of sensory neurons and synaptic function, contributing to an alteration of central sensory integration. High estimates of heritability and a genetic architecture shared with traits such as alexithymia highlight the convergence of sensory processing and the genetics of emotional regulation. In addition, neuro-immune signaling pathways interact with synaptic mechanisms to modulate the function and sensitivity of sensory neurons.