Autism is characterized by impairment in reciprocal communication and speech, repetitive behaviors, and social communication. The genetic and environmental factors play roles in the pathogenesis of autism. It was recently shown that the genes involved in the folate/homocysteine pathway may be risk factors for autistic children. One of the genes that may be the risk factor for autism is Methionine synthase (MTR). MTR is responsible for the regeneration of methionine from homocysteine. The aim of this study was to analyze the association of MTR A2756G gene polymorphism (rs1805087) and the risk of autism in a population in northern Iran. The prevalence of MTR A2756G polymorphism was determined in 108 children with autism and 130 controls in northern Iran. Genotypes and allele frequencies were determined in patients and controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The prevalence of genotype frequencies of AA, AG and GG in autistic children were 57.41%, 22.22% and 20.37%, respectively, while in controls were 61.54%, 32.31% and 6.15%, respectively. There was significant difference between the MTR polymorphism distribution in control and patient groups. The prevalence of allele frequencies of A and G in autistic children were 0.69 and 0.31, respectively and in controls were 0.78 and 0.22, respectively (P=0.03). The MTR G allele conferred a 1.6-fold increased risk to autism relative to the A allele (95% CI=1.06-2.41, P=0.02). The present study suggests that the G allele of MTR A2756G polymorphism is associated with an increased risk of autism.

The aim of this project was to evaluate the relationship of matrix metalloproteinase-9 (MMP-9) genetic variation and its serum concentration with autism spectrum disorder (ASD). One hundred ASD and 120 controls were enrolled in this study. Genomic DNA was extracted from blood and MMP-9 polymorphism was determined by polymerase chain reaction restriction fragment length polymorphism and serum levels were measured by enzyme-linked immunosorbent assay. The frequencies of CC, CT, and TT genotypes were 72%, 26%, and 2% in controls and 31%, 57%, and 12% in ASD, respectively. The frequencies of C and T alleles in ASD were 59.5% and 40.5%, and controls were 86% and 14%, respectively. There is a significant increase in serum MMP-9 levels in ASD as compared to controls. We have also shown that TT genotype is significantly associated with increase serum MMP-9 levels in patients (TT, CT, and CC serum levels were 91.77 ± 10.53, 70.66 ± 7.21, and 38.66 ± 5.52 and in controls were 55.55 ± 11.39, 42.66 ± 7.85, and 30.55 ± 6.34 ng/ml, respectively). It is concluded that there is a significant association between rs3918242 MMP-9 polymorphism and its serum concentration with autism. We also suggest that TT genotype is associated with increased MMP9 expression and may be a risk factor for ASD.

Introduction: MicroRNAs (miRNAs) are small ribonucleic acids that modulate the expression of downstream target genes. There is considerable evidence of their involvement in many malignancies, such as oesophageal and gastric. We hypothesised altered expressions of pri-miR-124-1 rs531564 and STAT3 rs1053023 polymorphisms in gastric cancer. Materials and methods: Genomic DNA was extracted from peripheral blood of 250 patients with gastric cancer and 310 healthy individuals. The RFLP method was applied for determination of pri-miR-124 polymorphism and the AS-PCR method for STAT3 polymorphism. Results: The distribution of rs531564 genotypes in cases and controls was different: the G allele carriers had a reduced gastric cancer risk (OR = 0.62; 95%CI = 0.49–0.80, P = 0.0002). Presence of the minor allele of STAT3 (rs1053023) was linked with higher risk of gastric cancer (OR = 2.29; 95% CI = 1.79–2.93, P < 0.0001). Compared with the most frequent haplotype C-G [the SNP order was pri-miR-124-1 (rs531564) and STAT3 (rs1053023)] in controls, C-A haplotype was associated with a significantly increased risk of gastric cancer (OR = 2.28; 95%CI = 1.64–3.09, P < 0.0001). Conclusion: There is a strong link between pri-miR-124-1 rs531564 and STAT3 rs1053023 and gastric cancer that may be pathogenic, and so worthy of further investigation.