This GWAS meta-analysis confirmed one previously identified locus on chromosome 8 as associated with cannabis use disorder and identified a new locus on chromosome 7. The lead variant at the chromosome 7 locus (rs7783012) is a cis-eQTL for FOXP2 expression in brain and adipose tissue. FOXP2 was also significantly implicated in gene-based tests that incorporated information about chromatin interactions in iPSC-derived astrocytes (appendix p 29). rs7783012 has also been associated with measures related to externalising behaviours (eg, ADHD,20 age at first sexual intercourse,51 generalised risk tolerance)52 and with educational attainment.47 FOXP2 is essential to synaptic plasticity and has been implicated in the normal development of speech and language acquisition53 However, because of the prominence of the protein product of FOXP2 as a regulator of numerous genes, indirect pathways of vulnerability beyond risk-taking are also possible.
