Abstract
Obsessive-compulsive disorder (OCD) and Tourette disorder (TD) are neuropsychiatric disorders in which genetic factors play a substantial, and very often shared, role in both disorders. This chapter reviews the current literature on the genetics of OCD and TD, including genetic epidemiology within and across disorders, familiality, candidate gene studies, genome-wide association studies (GWAS), copy number variants (CNVs), imaging genetics, pharmacogenetics, epigenetics, and gene-environment interaction.