Three recently published, family-based association studies have suggested SLC1A1 to be a candidate gene for OCD.16-18 However, no given SNP within SLC1A1 in these 3 studies was consistently positively associated with OCD across the 3 studies when tested individually, with the exception of rs3780412, which was considered significant in 2 studies: the overall and males-only study by Dickel and coworkers17 and in the males-only sample by Stewart and colleagues.18 However, our results do not support a specific involvement of this marker in OCD, nor did we observe any preferential or stronger association of single variants or haplotypes in males compared with females in our case-control sample (Table 1 and Table 2). Speculatively, this observation might be related to the increased power of our case-control design compared with the family-based studies published previously.16-18 Clearly, additional studies are warranted to clarify the discrepancy for preferential association in males observed in prior family-based studies,16-18 though the overall finding of involvement of SLC1A1 in OCD now appears more clearly replicable.
