The most significant SNP (rs78587207 (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$P=5.28\times 1{0}^{-12}$$\end{document}P=5.28×10−12)) identified in the GWAS is located on chr11q12.1 and has been previously associated with several traits, including neuropsychiatric phenotypes39 such as depressive symptoms40 and neuroticism40. Gene-based analyses identified four putative causal genes within this locus. The closest gene to rs78587207 is CTNND1, which encodes the cell adhesion molecule p120 catenin. This gene was associated with OCD using three gene-based tests (mBAT-combo, TWAS and PWAS), and we found strong evidence for colocalization of the TWAS signal for CTNND1 in the dlPFC. The dlPFC has been consistently implicated in the neural circuitry of OCD as well as in compulsivity more broadly as part of the cortico–striatal–thalamo–cortical circuitry41,42. The protein product of CTNND1 is a regulator of cell–cell adhesion43 and has a crucial role in gene transcription, Rho GTPase activity and cytoskeletal organization44–46. Other credible causal genes in the locus include CLP1 (cleavage factor polyribonucleotide kinase subunit 1), TMX2 (thioredoxin-related transmembrane protein 2) and ZDHHC5 (zinc finger DHHC type palmitoyltransferase 5). Rare genetic mutations in CLP1 are
