A common variant of the CNTNAP2 gene is associated with structural variation in the left superior occipital gyrus

•Associations of CNTNAP2 with brain imaging phenotypes lack independent replication.•We report a candidate gene association study on the rs7794745 CNTNAP2 SNP.•Partial replication of Tan et al., 2010 in a substantially larger sample (N = 1717).•The rs7794745 T allele is associated with dorsal visual grey matter reduction.

The CNTNAP2 gene encodes a cell-adhesion molecule that influences the properties of neural networks and the morphology and density of neurons and glial cells. Previous studies have shown association of CNTNAP2 variants with language-related phenotypes in health and disease. Here, we report associations of a common CNTNAP2 polymorphism (rs7794745) with variation in grey matter in a region in the dorsal visual stream. We tried to replicate an earlier study on 314 subjects by Tan et al. (2010), but now in a substantially larger group of more than 1700 subjects. Carriers of the T allele showed reduced grey matter volume in left superior occipital gyrus, while we did not replicate associations with grey matter volume in other regions identified by Tan et al. (2010). Our work illustrates the importance of independent replication in neuroimaging genetic studies of language-related candidate genes.