Prevalence of the methylenetetrahydrofolate reductase 677C>T polymorphism in the pregnant women of Yunnan Province, China

Abstract

Mutations in the methylenetetrahydrofolate reductase ( MTHFR ) gene can result in a reduced ability to utilize folic acid. The MTHFR 677C>T polymorphism in particular has been linked to both birth defects and pregnancy-associated diseases. This study aimed to evaluate the prevalence of the MTHFR 677C>T mutation among pregnant women in Yunnan Province so as to collect baseline data that may be utilized to guide folic acid supplementation efforts and to support related disease prevention programs. We retrospectively reviewed 3387 pregnant women from Yunnan Province. The MTHFR 677C>T polymorphism was identified using polymerase chain reaction (PCR) and DNA sequencing. In total, 1350 (39.9%) subjects were homozygous for the C allele (CC), 1540 (45.4%) subjects were heterozygous (CT), and 497 (14.7%) subjects were homozygous for the T allele (TT). The MTHFR 677C>T polymorphism was found to be present within the studied population, with ∼60% of these patients being either heterozygous or homozygous for the mutant allele and with an overall T allele frequency of 0.37. The frequency of the T allele was significantly higher among pregnant women with complications relative to women with healthy pregnancies, particularly among women <30 years old. As such, the maternal MTHFR 677C>T polymorphism may be a genetic risk factor associated with pregnancy complications and may help identify pregnant women at a high risk of such complications.

More evidence for widespread antagonistic pleiotropy in polymorphic disease alleles

“…At position 677 of MTHFR there is a C/T SNP and individuals heterozygous or homozygous for the T nucleotide produce a MTHFR protein with reduced activity which leads to lower levels of folate and higher levels of homocysteine in the blood. Clinically, in addition to increased risks of a variety of birth defects from the presence of the T allele ( Pi et al, 2020 ), is also associated with higher risks of schizophrenia ( Lewis et al, 2005 ), male infertility ( Karimian and Colagar, 2016 ; Aliakbari et al, 2020 ), gestational diabetes ( Tan and Chen, 2023 ) and recurrent pregnancy loss ( Wu et al, 2012 ) in Asians, and Alzheimer’s disease in Asians ( Hua et al, 2011 ; Peng et al, 2014 ) and APOE4 carriers ( Peng et al, 2014 ). At position 1,298 of MTHFR there is an A/C SNP with a similar biochemical effect but where the effects of the C allele are generally less severe, but evidence shows an association with increased cervical cancer risk ( Yi et al, 2016 ) and reduced sperm counts in Asian ( Aliakbari et al, 2020 ), Moroccan ( Eloualid et al, 2012 ), and Indian ( Singh et al, 2010 ) populations.…”