B-238 Genotypic Frequency of the C677T and A1298C Variants of the MTHFR Gene in Patients with Infertility and Fetal Loss

Background Female infertility affects a significant number of women worldwide. It is defined as the inability to achieve pregnancy after one year of regular attempts without the use of contraceptive methods. Among the obstetric complications associated with infertility, recurrent miscarriage stands out, characterized by the occurrence of two or more consecutive miscarriages. The MTHFR gene (methylenetetrahydrofolate reductase) encodes the homonymous enzyme responsible for catalyzing the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, the active form of folate, which is essential for cellular metabolism. Polymorphisms in this gene, such as C677T and A1298C, are associated with reduced enzymatic activity, affecting folate metabolism with its recognized impact on the prevention of neural tube defects. Low levels of folic acid, associated with increased homocysteine concentrations, are linked to recurrent miscarriages and other pregnancy complications. The aim of this study was to determine the genotypic frequency of the C677T and A1298C polymorphisms of the MTHFR gene in patients with infertility and recurrent miscarriage. Methods This study analyzed 759 samples from 253 female patients undergoing investigation for reproductive difficulties. Clinical samples were collected and subjected to karyotype analysis (n=253) and detection of two mutations in the MTHFR gene (n=506). Karyotype analysis was performed using G-banding techniques, according to the protocols established by the International System for Human Cytogenomic Nomenclature (ISCN). For MTHFR gene mutation testing, real-time Polymerase Chain Reaction (PCR) was employed. The alleles analyzed included C677T and A1298C, the main variants associated with altered enzymatic function. The inclusion criteria were patients with a history of infertility and recurrent miscarriage, aged between 21 and 50 years, and the availability of complete results for both genetic tests. Results All 253 samples analyzed showed normal results for karyotype analysis. Considering the MTHFR gene polymorphisms, the overall mutation frequency was 53.75% (272/506) for the analyzed alleles. When evaluating the polymorphisms individually, 14.62% of patients had no mutations, 37.15% presented mutation in C677T, and 26.1% in A1298C. Furthermore, 22.13% of patients had mutations in both polymorphisms. The heterozygous mutation was predominant for both polymorphisms, observed in 79.33% for C677T and 87.70% for A1298C. Among the patients with mutations in both polymorphisms, all exhibited heterozygous mutations (100%). Homozygous mutations were found in 20.66% for C677T and 12.29% for A1298C. Regarding age group, the prevalence of mutations was observed in patients between 31 and 40 years old, who represented 64.82% of the cases analyzed. In this age group, the primary reason for the investigation was infertility, accounting for 70.12% of diagnostic hypotheses, while 29.88% of cases were related to recurrent miscarriage. Conclusion The results highlighted the high frequency of the C677T and A1298C polymorphisms of the MTHFR gene in patients with a history of infertility and recurrent miscarriages, reinforcing the relevance of these variants in the context of reproductive health. The prevalence of heterozygous mutations in both polymorphisms, as well as the genetic alterations observed in women aged 31 to 40 years, indicate the need to consider the impact of these genetic factors during clinical evaluation of infertility and pregnancy complications.