The serotonin-1Dbeta receptor gene and severity of obsessive-compulsive disorder in women with bulimia nervosa.
BACKGROUND
There is significant evidence that eating disorders have an important biological overlap with obsessive-compulsive disorder (OCD), though the specific mediators of this relationship remain unclear. Recent evidence suggests that the G861C polymorphism of the 5HT-1Dbeta receptor gene and the G allele in particular may play a role in OCD. We thus hypothesized that, among a heterogenous group of probands with bulimia nervosa (BN), this same G allele might predict the presence and/or severity of OCD pathology.


METHODS
165 consecutive female probands with BN were genotyped for the G861C polymorphism of the 5HT-1Dbeta receptor gene. Rates of full syndrome OCD, partial syndrome OCD and no OCD were compared across the three genotypic groups defined by this polymorphism.


RESULTS
45 out of 165 BN probands (27.3%) had either full or partial syndrome OCD. In the full sample, there was a significant difference in the distribution of the three diagnostic groups by genotype (chi2=10.07, df=4, p=.039). The G861C polymorphism did not strongly predict which probands had any vs. no OCD pathology. However, among the 45 probands with OCD symptoms, the G861C polymorphism did strongly differentiate full syndrome vs. partial syndrome OCD (chi2=9.26, df=2, p=.01; odds ratio for full syndrome OCD with GG genotype=7.69, 95% CI=1.45-40.9).


CONCLUSIONS
In women with BN, the G861C polymorphism of the 5HT-1Dbeta gene does not appear to be associated with the generation of OCD symptoms; however, it might directly or indirectly be associated with a modulatory effect on syndrome severity in probands otherwise predisposed to OCD. While preliminary and in need of replication in other samples, this is the first association study to suggest how a particular gene might influence OCD pathology in an eating disorder population.
Levitan
R D
RD
Mood and Anxiety Division, Centre for Addiction and Mental Health, University of Toronto, Department of Psychiatry, Canada. robert_levitan@camh.net
Kaplan
A S
AS
Masellis
M
M
Basile
V S
VS
Richter
M A
MA
Kennedy
J L
JL
D000293:Adolescent; D000328:Adult; D052018:Bulimia Nervosa / Q000209:etiology* / Q000235:genetics*; D016009:Chi-Square Distribution; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D015810:Linkage Disequilibrium; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000150:complications* / Q000235:genetics*; D011110:Polymorphism, Genetic; D011569:Psychiatric Status Rating Scales; D044302:Receptor, Serotonin, 5-HT1B / Q000235:genetics*; D012720:Severity of Illness Index
D044302:Receptor, Serotonin, 5-HT1B