The goal of this study was to see if the methylenetetrahydrofolate reductase (MTHFR) variations in the Saudi community altered susceptibility to the risk of autistic spectrum disorder (ASD).
Methods and Subjects: The severity of ASD symptoms was assessed using diagnostic and statistical manual of mental disorders (DSM-V) criteria and scores on the childhood autism rating scale (CARS). TaqManTM genotyping assays for the 677C>T rs1801133 and 1298A>C rs1801131 SNPs in the MTHFR gene were used to assess genomic DNA from buccal cells of 112 patients with ASD and 104 healthy controls. The optimum interactive inheritance method for selected SNPs was determined using the SNPStats software (https://www.snpstats.net). The protein-protein interaction network of the MTFR gene was predicted using the Search Tool for the Retrieval of Interacting Genes (STRING) database (https://string-db.org).
Controls in the studied SNPs were compatible with Hardy-Weinberg equilibrium. The MTHFR rs1801133 C>T and MTHFR rs1801131 A>C SNPs were shown to have associated with ASD risk (odds ratio [OR]= 5.2 and 22.2, respectively). In cases vs controls, genotype relationships of these SNPs were statistically significant (P= 0.0012 and P= 0.0008, respectively). The SNPs studied were shown to be strongly linked to ASD cases with a score of 37 (codominant and recessive models; P= 0.001 and P= 0.0005, respectively). The C/C-A/A genotype was the most prevalent among six combination genotypes in ASD cases (42.9 percent ). A substantial variation in haplotype distribution between patients and controls was found in a global haplotype analysis (P=0.00057). The two SNPs were discovered to be in linkage disequilibrium (D’= 0.63, r2 = 0.260).
Conclusion: The MTHFR rs1801133 and rs1801131 SNPs interact to increase the risk of ASD, particularly when verified in larger cohorts with other genetic/environmental factors. Our findings could be used to support future genetic association research in the Saudi population, as well as government and health-care professionals working on regional health-management efforts.
Nasser A. Elhawary
Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Mecca 21955, P.O. Box 57543, Saudi Arabia.