There have been numerous candidate gene association studies in OCD 10. A positional candidate of particular interest is the neuronal and epithelial glutamate transporter gene (SLC1A1). It is located in the region of the replicated linkage peak on chromosome 9p24, and there is considerable evidence from imaging, animal, and treatment studies that abnormal glutamatergic transmission may be involved in the pathophysiology of OCD 11, 12. Several studies have reported positive associations of OCD with this gene, but with different SNPs in each 13–19. A recent meta-analysis of these studies did not resolve the issue and was not able to report experiment-wise significance for SNPs annotated to SLC1A1 20.
