Association study of the vesicular monoamine transporter 1 (VMAT1) gene with schizophrenia in a Japanese population

Abstract

Background: Vesicular monoamine transporters (VMATs) mediate accumulation of monoamines such as serotonin, dopamine, adrenaline, and noradrenaline from the cytoplasm into storage organelles. The VMATI (alternatively solute carrier family 18: SLC18A1) regulates such biogenic amines in neuroendocrine systems. The VMATI gene maps to chromosome 8p21.3, a locus with strong evidence of linkage with schizophrenia. A recent study reported that a non-synonymous single nucleotide polymorphism (SNP) of the gene (Pro4Thr) was associated with schizophrenia. Methods: We attempted to replicate this finding in a Japanese sample of 354 schizophrenics and 365 controls. In addition, we examined 3 other non-synonymous SNPs (Thr98Ser, Thr136lle, and Va1392Leu). Genotyping was performed by the TaqMan allelic discrimination assay. Results: There was no significant difference in genotype or allele distribution of the three SNPs of Pro4Thr, Thr136lle, or Va1392Leu between patients and controls. There was, however, a significant difference in genotype and allele distributions for the Thr98Ser polymorphism between the two groups (P = 0.01 for genotype and allele). When sexes were examined separately, significant differences were observed in females (P = 0.006 for genotype, P = 0.003 for allele), but not in males. The Thr98 allele was more common in female patients than in female controls (odds ratio 1.69, 95% Cl 1.19-2.40, P = 0.003). Haplotype-based analyses also provided evidence for a significant association in females. Conclusion: We failed to replicate the previously reported association of Pro4Thr of the VMATI gene with schizophrenia. However, we obtained evidence for a possible role of the Thr98Ser in giving susceptibility to schizophrenia in women. © 2006 Richards et al; licensee BioMed Central Ltd.