A study of MTRR 66A>G gene polymorphism in patients with autism from northern Iran

Autism is a neurodevelopmental disorders that manifests before 3 years of age, more common in boys. Whereas causes of autism remain uncertain, it is influenced by genetic and environmental factors. Recent studies have shown that the genes involved in the folate metabolism pathway may play an important role in autism. Methionine synthase reductase (MTRR) is a key enzyme that plays an important role in the homocysteine/folate metabolism and has been shown to be implicated in neurological disorders including autism. In this study, 356 subjects were studied, which consists of 142 autistic children and 214 nonautistic control. Genomic DNA was extracted from blood samples. Genotype of MTRR 66A>G gene was performed using polymerase chain reaction-allele specific PCR (AS-PCR). The genotype frequencies of AA, AG and GG in the children with autism were 9.9%, 76.0% and 14.1%, respectively and in control group were 13.1%, 86.0% and 0.9%, respectively. The allele frequencies of A, G in the children with autism were 48.0%, 52.0%, respectively and in control group were 56.0%, 44.0%, respectively. Statistical analysis showed that there is a significant correlation in the genotype between two groups (OR=20, 95% CI=4.1 to 98, P<0.001). It is concluded that MTRR A66G polymorphism is associated with autism in a population in northern Iran. More studies with larger number should be done to confirm this result.

Analysis of methionine synthase reductase polymorphism (A66G) in Indian Muslim population.

BACKGROUND AND OBJECTIVES: Methionine synthase reductase (MTRR) is a vital enzyme of homocysteine/methionine metabolic pathway and is required for the conversion of inactive form of methionine synthase (MTR) to its active form. A clinically important allelic variant of MTRR A66G, with less enzymatic activity is reported with worldwide prevalence rate of ~ 30%. The present study was designed to determine the frequency of MTRR A66G polymorphism in rural Sunni Muslim population of Eastern Uttar Pradesh. MATERIALS AND METHODS: Total 56 subjects were analyzed for MTRR A66G polymorphism. A66G mutation analysis was carried out according to the polymerase chain reaction-restriction fragment length polymorphism method of Wilson et al. [1] amplification with MTRR specific primers followed by amplicon digestion with NdeI enzyme was used for the identification of different MTRR genotypes in subjects. RESULTS AND DISCUSSION: The AA genotype was found in 5 subjects, AG in 23 subjects, and GG genotype in 28 subjects. Genotype frequencies of AA, AG, and GG were 0.089, 0.41, and 0.5 respectively. The allele frequency of A allele was found to be 0.298 and G allele was 0.705. CONCLUSION: It is evident from the present study that the percentage of homozygous genotype GG and frequency of G allele is high in the target Muslim population.

MTRR A66G polymorphism among two caste groups of Uttar Pradesh (India).

Objective: This study was aimed to evaluate the Methionine synthase reductase (MTRR) A66G mutation in Yadav and Scheduled Caste (SC) population of Uttar Pradesh. Materials and Methods: Blood samples were collected from 100 subjects after taking informed written consent and PCR-RFLP method was used for the analysis of A66G mutation. After NdeI digestion, 66-bp amplicon of normal allele was cut into 22- and 44-bp long fragments, whereas mutant G allele was not digested. Results: Frequencies of genotypes in Yadav population AA, AG, and GG were 12%, 60%, and 28%, respectively, and in SC population, genotypic frequencies were 12% (AA), 52% (AG), and 36% (GG). Conclusion: MTRR gene A66G mutation is found to be polymorphic in both the target populations with G allele frequencies being 0.58 for Yadav and 0.62 for Scheduled Caste.