Association study of the vesicular monoamine transporter 1 (VMAT1) gene with autism in an Iranian population.

Autism Spectrum Disorders (ASD) (MIM 209850) are a group of neurodevelopmental disorders distinguished by destructed social interaction and communication abilities along with peculiar repetitive behavior. Several genetic loci have been linked to this disorder. Vesicular monoamine transporter 1 (VMAT1/SLC18A1) is an attractive candidate gene for psychiatric disorders because of its participation in regulation monoamines. In the present case-control study, we evaluated the link between three non-synonymous single nucleotide polymorphisms (SNPs) (rs2270641 [Pro4Thr], rs2270637 [Thr98Ser] and rs1390938 [Thr136Ile]) and one intronic SNP (rs2279709) across the VMAT1 gene and ASD in a group of Iranian patients. Allele frequency analyses showed significant over-presentation of rs1390938-G allele in cases compared with controls (P<0.001). The analysis under different genetic models showed that the AA genotype of the rs1390938 was protective against ASD under dominant and recessive models. The rs2270641 SNP was associated with ASD risk only in over-dominant model. Other SNPs showed no significant difference in allele or genotype frequencies between two groups. Haplotype analysis revealed that C A T T and C A T G haplotypes (rs2270637, rs1390938, rs2279709 and rs2270641 respectively) have a protective effect against ASD. Consequently, the functional rs1390938 SNP in VMAT1 is associated with ASD in Iranian population. Considering the role of VMAT1 in regulation of monoamines, the dysregulated expression of this protein during early stages of brain development might be implicated in ASD.