AS3MT and schizophrenia: In addition to rare tandem repeat expansions in schizophrenia, several recent studies have identified common tandem repeat variation, VNTRs, that influence schizophrenia risk within GWAS-positive loci (Fig. 1): (i) within a highly ranked schizophrenia GWAS-positive locus, 10q24.32, a VNTR in exon 1 of AS3MT was found to be in linkage with the GWAS index SNP and to have a functional effect on cis-gene expression [47].