SLC6A4 and anxiety disorder: For example, we cannot comment on the previously reported role of the MAOA-u variable number tandem repeat in CBT response.43 Nor could we assess the effect of the 5HTTLPR variant of SLC6A4, previously associated with remission from anxiety disorders at follow-up; however, we directly genotyped this variant in this cohort, and were unable to replicate our earlier finding.8,10