Association between polymorphisms of SLC6A3 and DRD1 genes and autism among Saudi Arabia Taif population using PCR-restriction fragment length polymorphism (PCR- RFLP)

Abstract

The prevalence of autism in Saudi Arabia is 18 per 10,000, higher than the 13 per 10,000 reported in developed countries. The etiology of autism is still not completely understood. Different studies support the involvement of dopaminergic neurotransmitter system in the etiology of autism. Several lines of evidences suggest the role of some dopamine related genes, such as DRD1 and SLC6A3 in the etiology of autism. The aim of the present work was to study the possible role of rs2550936 A/C polymorphism at SLC6A3 locus as well as rs4532 A/G polymorphism at DRD1 locus in the etiology of autism among Saudi population. The polymorphisms of DRD1 and LC6A3 were genotyped in the case-control study using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Significant association as risk factor was found between autism and GA genotype of DRD1 [OR = 3.5 CI (1.04, 12.41*)] as well as CA genotype of SLC6A3 [OR = 2.53 CI (1.03, 6.26*)], while CC genotype of SLC6A3 revealed protective effect. In conclusion, possible risk genotypes for autism in the DRD1 and SLC6A3 genes were observed. This is the first report in Saudi Arabia population and Arab world. Therefore further investigations of these markers and other SNPs of SLC6A3 and DRD1 genes are considered in large replication samples with other causal factors to enable positive identification of risk genotypes and generalize obtained results. Key words : Etiology, polymorphism, autism, genotype.