Neuronal nitric oxide synthase polymorphisms in obsessive-compulsive disorder.

BACKGROUND: Obsessive-compulsive disorder (OCD) is a mental disease characterized by recurrent and intrusive thoughts and repetitive behaviours that negatively affect the quality-of-life of the patients. Recent studies have implicated the participation of neuronal nitric oxide in OCD pathogenesis as a neurotransmitter modulator.

AIMS: To identify whether variations in neuronal nitric oxide synthase (nNOS) genes may render individuals susceptible to OCD development.

METHODS: This study examined nNOS polymorphisms in 100 OCD patients and 121 unrelated healthy controls by polymerase chain reaction and restriction enzyme digestion methods.

RESULTS: nNOS 276 C + genotype incidence was significantly higher in OCD patients than controls and conferred a 2-fold increased risk for OCD. No significant differences were observed in frequencies of nNOS 84 genotypes between patients and controls.

CONCLUSION: This study shows an association between nNOS gene polymorphism and OCD. Exact mechanisms by which nNOS gene variants contribute to OCD pathogenesis need to be further investigated.