Excessive grooming and anxiety-like behaviors have been observed in mice lacking expression of SAPAP3, a post-synaptic scaffolding protein located at excitatory synapses. This finding, coupled with high SAPAP3 expression levels in the striatum, identify its human ortholog (DLGAP3) as an appealing candidate gene in OCD.33 Human studies have provided some support for a possible role of DLGAP3 in OCD-related disorders, suggesting increased rare non-synonymous variant frequencies in OCD/trichotillomania subjects34 and association of common DLGAP3 variants with pathologic grooming in a family-based study,35 albeit with some inconsistencies.36
