PROJECT SUMMARY Tandem repeats are a prevalent class of genomic variant, prone to high frequency of mutation and known to underlay some neurological disorders, including the trinucleotide repeat disorders, Huntington’s Disease and spinocerebellar ataxias. To date, a systematic investigation of the role of TRs in schizophrenia has not yet been conducted, partly owing to technical limitations in genotyping tandem repeats, as well as lack of access to large- scale, sequenced schizophrenia cohorts. The goal of the current project is to apply recently developed TR profiling tools to whole genome sequenced (WGS), schizophrenia cohorts to identify variation in short tandem repeats (STRs) and variable number tandem repeats (VNTRs), that may contribute to schizophrenia genetic risk. The proposed systematic study of TR variation in schizophrenia has a high likelihood of uncovering novel genetic risk factors. The study will leverage innovative algorithms for high-throughput TR genotyping applied to large and well-powered schizophrenia cohorts. Therefore, this timely and well-powered approach could lead to novel insights into the role of tandem repeat variation in schizophrenia and human disease, with important translational implications.