Dopamine system genes not linked to social Phobia

Social phobia, particularly in its generalized form, has a genetic component in its etiology as suggested by positive twin studies and child temperament studies of social anxiety. Observations from functional imaging research suggest that dopamine function may be abnormal in the brains of patients with social phobia. Our investigation examined polymorphisms in the dopamine D2, D3 and D4 receptor genes, plus the dopamine transporter gene in a sample consisting of 17 multiplex social phobia families. We employed both parametric and non-parametric methods to test for linkage. Linkage was excluded for all loci under the broad diagnostic category. In the medium diagnostic category, the D3 receptor gene showed non-significant positive LOD scores (LOD = 0.62). We are able to clearly exclude a major effect for each of the four dopamine gene markers under the broad diagnosis of social phobia. Additional studies of dopamine system genes will be necessary to define clearly their role in social phobia. Psychiatr Genet 11:213-217 (C) 2001 Lippincott Williams Wilkins.