Increased expression of genetically-regulated FLT3 implicated in Tourette Syndrome

Abstract

Tourettes Syndrome (TS) is a neurodevelopmental disorder that is characterized by motor and phonic tics. A recent TS genome-wide association study (GWAS) identified a genome-wide significant locus. However, determining the biological mechanism of GWAS signals remains difficult. Here, we conduct a TS transcriptome-wide association study (TWAS) consisting of 4,819 cases and 9,488 controls and found that increased expression of FLT3 in the dorsolateral prefrontal cortex (DLPFC) is associated with TS. We further showed that there is global dysregulation of FLT3 across several brain regions and probabilistic causal fine-mapping of the TWAS signal prioritizes FLT3 with a posterior inclusion probability of 0.849. We validated the genes expression in 100 lymphoblastoid cell lines, establishing that TS cells had a 1.72 increased fold change compared to controls. A phenome-wide association study points towards FLT3 having links with immune-related pathways such as monocyte count. We also identify several splicing events in MPHOSPH9, CSGALNACT2 and FIP1L1 associated with TS, which are also implicated in immune function. This analysis of expression and splicing begins to explore the biology of TS GWAS signals.