Background: Obsessive-compulsive disorder (OCD) is a common, serious and genetically related mental illness; the etiology of OCD has not yet reached a definitive conclusion. Multiple evidence suggests that the glutamatergic system plays a major role in the pathophysiology of OCD. However, subsequent studies on the glutamate transporter gene are not consistent. OCD is a heterogeneous disease. To resolve the complex genetic basis of OCD, division the disorder into different subphenotypes is an effective method for studying the pathogenesis of OCD.
Methods: We recruited 438 OCD patients and 465 age- and sex-matched controls from a Chinese Han population. rs10491734, rs3780412, rs301434 and rs3087879  SNPs were genotyped by real-time TaqMan polymerase chain reaction, and the chi-squared test was used to compare allele and genotype frequencies of variants between the two groups.
Results: The genotype of rs301434  was statistically significant in total patients with OCD and the controls. After grouping by age and gender, the genotype of rs301434  was statistically significant in early-onset OCD, late-onset OCD as well as male OCD, the allele and genotype of rs3780412  was associated with late-onset OCD. Haplotype analysis showed that four loci haplotypes (G-A-A-G and G-G-A-G) were associated with total OCD, (G-G-A-G) was associated with female OCD, (G-A-G-G) was associated with male OCD, (G-A-A-G and G-G-A-G) were associated with late-onset OCD.
Conclusion: This study provides suggestive evidence that SLC1A1 may be involved in the development of OCD in the Han population. However, these findings require further replication.
Keywords: obsessive-compulsive disorder, glutamate transporter gene, haplotype