Polymorphisms of the MTHFR Gene in Mothers of Children with Trisomy 21 (Down Syndrome) in a Polish Population

Abstract

Background: Down Syndrome (DS) is the most frequent cause of intellectual disability. In 95% of cases, it is caused by simple trisomy of chromosome 21 resulting from nondisjunction of chromosomes in meiotic division. Currently, the molecular and cellular mechanisms responsible for the phenomenon of nondisjunction are unknown. In this paper, we evaluated the incidence of five single-nucleotide polymorphisms (SNPs) of the MTHFR gene in a population of Polish mothers who had given birth to children with trisomy 21 in comparison with a control group of women with healthy offspring. Methods: The test material comprised venous blood collected from mothers who had given birth to a child with Down syndrome (study group, n = 130) as well as from women who had given birth to children without trisomy 21 (control group, n = 88). DNA was isolated using a kit manufactured by Qiagen. Amplification was carried out using a Qiagen Multiplex PCR Kit (Qiagen); genotyping was performed using SNaPshot Genotyping MasterMix (Applied Biosystems). Results: No statistically significant differences were observed in the frequency of genotypes between the examined groups in terms of the polymorphisms of the MTHFR gene. Conclusions: In the studied Polish population, no relationship was found between the occurrence of particular genotypes of the MTHFR gene, i.e. 677CT, 1298AC, rs3737964, rs4846048, and rs1994798, in women and the birth of children with trisomy 21. The results contradict the validity of research on polymorphisms of the MTHFR gene as potential predisposing factors for the occurrence of trisomy 21 in children.