The applicant for the purpose of having a baby with down's syndrome in pregnant women prenatal diagnosis and relationship between maternal methylenetetrahydrofolate reductase genotype

Down Syndrome or Trisomi 21 is the most common genetic disease releated with expression of 3 copies located on 21. choromosome genes. This situation, about 90% of cases, originate from maternal choromosome nondisjunction during meiosis. In recent years, the relation between choromosome nondisjunction and folate metabolism has begun to drawn attention. Folate has an important function the distiribution of genetic material during segmentation because of its function, which is epigenetic regulatory in segmentation and other stages, in cellular methylation reactions. MTHFR (Methylenetetrahydrofolate Reductase); catalyzes the transformation of 5,10- Methylenetetrahydrofolate to 5- Methyltetrahydrofolate, which is a methyl transmitter, for remethylation of homocysteine to methionine. MTHFR is effective in important pathways as DNA synthesis and methylation reactions. The most common polymorphisms occuring in MTHFR gene are C677T (1801133) ve A1298C (1801131). The objective of this study is to explore the relation between the condition of having children with Down Syndrome and maternal MTHFR C677T and A1298C polymorphisms. Besides, homocysteine and folate levels were also determined in case and control groups. A statistically significant difference was determined between case and control groups in terms of genotype and allele frequencies for C677T polymorphism (p<0.05). While the rate of individuals with normal genotype was 9% in case group, it was observed 42.4% in control group. The rate of homozygous individuals were determined similar (%16.4-%16.7). While the rate of T allele frequency (%53.7) was great in case group, the rate of C allele frequency (%62.9) was determined great in control group. On the other hand, no significant difference was observed in terms of genotype and allele frequencies between in case and control groups for A1298C polymorphism (p>0.05). When serum folate and homocysteine levels were compared, a significant difference was observed statistically in case and control groups. The average level of serum folate (ng/mL) and homocysteine (nmol/mL) were observed within the case and control groups 6.05; 7.85/ 13.46;18.14, respectively.