Investigation of gene–environment interactions in relation to tic severit

Abstract

Tourette syndrome (TS) is a neuropsychiatric disorder with involvement of genetic and environmental factors. We investi gated genetic loci previously implicated in Tourette syndrome and associated disorders in interaction with pre- and perinatal adversity in relation to tic severity using a case-only (N=518) design. We assessed 98 single-nucleotide polymorphisms (SNPs) selected from (I) top SNPs from genome-wide association studies (GWASs) of TS; (II) top SNPs from GWASs of obsessive–compulsive disorder (OCD), attention-defcit/hyperactivity disorder (ADHD), and autism spectrum disorder (ASD); (III) SNPs previously implicated in candidate-gene studies of TS; (IV) SNPs previously implicated in OCD or ASD; and (V) tagging SNPs in neurotransmitter-related candidate genes. Linear regression models were used to examine the main efects of the SNPs on tic severity, and the interaction efect of these SNPs with a cumulative pre- and perinatal adversity score. Replication was sought for SNPs that met the threshold of signifcance (after correcting for multiple testing) in a rep lication sample (N=678). One SNP (rs7123010), previously implicated in a TS meta-analysis, was signifcantly related to higher tic severity. We found a gene–environment interaction for rs6539267, another top TS GWAS SNP. These fndings were not independently replicated. Our study highlights the future potential of TS GWAS top hits in gene–environment studies.