Synaptic processes and immune-related pathways implicated in Tourette Syndrome

Tourette Syndrome (TS) is a neuropsychiatric disorder of complex genetic architecture involving multiple interacting genes. Here, we sought to elucidate the pathways that underlie the neurobiology of the disorder through genome-wide analysis. We analyzed genome-wide genotypic data of 3581 individuals with Tourette Syndrome (TS) and 7682 ancestry-matched controls and investigated associations of TS with sets of genes that are expressed in particular cell types and operate in specific neuronal and glial functions. We employed a self-contained, set-based association method (SBA) as well as a competitive gene set method (MAGMA) using individual-level genotype data to perform a comprehensive investigation of the biological background of TS. Our SBA analysis identified three significant gene sets after Bonferroni correction, implicating Ligand-gated Ion Channel Signaling, Lymphocytic, and Cell Adhesion and Trans-synaptic Signaling processes. MAGMA analysis further supported the involvement of the Cell Adhesion and Trans-synaptic Signaling gene set. The Lympho-cytic gene set was driven by variants in FLT3, raising an intriguing hypothesis for the involvement of a neuroinflammatory element in TS pathogenesis. The indications of involvement of Ligand-gated Ion Channel Signaling reinforce the role of GABA in TS, while the association of Cell Adhesion and Trans-synaptic Signaling gene set provides additional support for the role of adhesion molecules in neuropsychiatric disorders.