Symmetry symptoms in obsessive-compulsive disorder: clinical and genetic correlates.
OBJECTIVE
In obsessive-compulsive disorder (OCD), symmetry-related symptoms may be important. Although clinical correlates of symmetry-related symptoms have been identified in OCD, few data exist on genetic associations. Animal studies indicate involvement of dopamine in symmetry-related behavior, suggesting this may be relevant to analogous symptoms in OCD. Alterations in dopamine may also reflect environmental influences. However, the association of symmetry-related symptomatology, early adversity, and polymorphisms in dopaminergic genes has not been investigated in OCD.


METHODS
Clinical information and polymorphisms in key dopaminergic genes were compared between OCD patients with primary symmetry symptoms and those without.


RESULTS
OCD patients with primary symmetry symptoms comprised 46.6% (n=210) of the sample (n=451), and were older (p < 0.01), had longer illness duration (p < 0.01), higher OCD severity scores (p = 0.01), and greater comorbidity (p < 0.01) than those without. In Caucasians (n=343), genotype frequency differed significantly between groups for ANKK1 rs1800497, with more OCD patients with symmetry symptoms being homozygous for the A2 (CC) genotype (χ2 = 7.296; p = 0.026).


CONCLUSIONS
Symmetry symptoms have some distinct clinical features and may represent a marker of severity in OCD. However, clinical associations, in combination with the association found with the ANKK1 rs1800497 A2 variant, suggest that primary symmetry symptoms may represent a distinctive clinical and psychobiological profile.
MRC Unit on Anxiety and Stress Disorders, Department of Psychiatry, University of Stellenbosch, Stellenbosch, South Africa.
Christine
C
Lochner
Department of Psychiatry, University of Stellenbosch, Stellenbosch, South Africa.
Nathaniel
N
McGregor
Department of Psychiatry, University of Stellenbosch, Stellenbosch, South Africa.
Sian
S
Hemmings
Centre of Excellence for Pharmaceutical Sciences, School of Pharmacy, North-West University, Potchefstroom, South Africa.
Brian H
BH
Harvey
MRC Unit on Anxiety and Stress Disorders, Department of Psychiatry, University of Stellenbosch, Stellenbosch, South Africa.
Elsie
E
Breet
Biostatistics Unit, Cape Town, South Africa.
Sonja
S
Swanevelder
MRC Unit on Anxiety and Stress Disorders, Department of Psychiatry, University of Stellenbosch, Stellenbosch, South Africa.
Dan J
DJ
Stein
D000293:Adolescent; D000328:Adult; D003865:Major Depressive Disorder / Q000150:complications; D004298:Dopamine / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000150:complications / Q000175:diagnosis* / Q000235:genetics*; D000072639:Perfectionism; D011110:Polymorphism, Genetic / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D012720:Severity of Illness Index; D013313:Stress Disorders, Post-Traumatic / Q000150:complications; D020080:Tandem Repeat Sequences / Q000235:genetics; D055815:Young Adult
C489948:ANKK1 protein, human; D017346:Protein Serine-Threonine Kinases; D004298:Dopamine