RESUMO
BACKGROUND: Methylenetetrahydrofolate reductase, the encoded by the MTHFR gene, plays a crucial role in converting the amino acid homocysteine to methionine. Two polymorphisms of the MTHFR gene, C677T and A1298C, reportedly reduce enzyme activity, resulting in hyperhomocysteinemia. Patients with C677T and A1298C polymorphisms may be at higher risk for developing abnormal hyperhomocysteinemia, which has been linked to catastrophic neurological including fatal outcomes. OBJECTIVE: Determine the prevalence of the MTHFR gene variants C677T and A1298C among pediatric dental patients treated at King Abdulaziz University Hospital. DESIGN: Cross-sectional. SETTING: Clinics of pediatric dentistry department. SUBJECTS AND METHODS: Healthy Saudi children 6-12 years old with no known allergies were screened for eligibility between May and December 2019. A single investigator collected saliva samples. The MTHFR C677T and A1298C polymorphisms were analyzed using polymerase chain reaction and restriction fragment length polymorphism. MAIN OUTCOME MEASURE: The prevalence of MTHFR gene variants (C677T and A1298C) among the subjects. SAMPLE SIZE: 138. RESULTS: MTHFR C677T polymorphism was present in 36.2% of the sample and 90.0% of children carrying this allele were heterozygotes. MTHFR A1298C polymorphism was present in 91.3% of the sample and 77.0% of the children carrying this allele were heterozygotes. No linkage disequilibrium between MTHFR C677T and MTHFR A1298C was observed within this sample. CONCLUSIONS: Our study found a high frequency of the MTHFR A1298C genotype, which was substantially more abundant than expected based on a Hardy-Weinberg distribution. Therefore, caution is advised in using N2O in Saudi children as the increased prevalence of this MTHFR allele may increase the incidence of serious adverse effects among these children. LIMITATIONS: Further studies are recommended with a larger sample size from randomly selected hospitals from different regions of Saudi Arabia. CONFLICT OF INTEREST: None.