Screening of six polymorphisms related with folate metabolism in parents of individuals with Down syndrome

Increased susceptibility for nonsyndromic cleft lip with or without cleft palate by SLC19A1 80G>A genetic variation

BACKGROUND

The disruption of craniofacial developmental pathways during early embryogenesis can lead to conditions such as nonsyndromic cleft lip with or without cleft palate (NSCL/P). Several lines of evidence indicate that inadequate maternal nutrition causes low folate levels during the periconceptional period, resulting in NSCL/P. Although substantial research has been conducted on the possible link between SLC19A1 genetic variants and NSCL/P, the association between SLC19A1 80G>A (rs1051266) and NSCL/P remains unclear. In the present study, the associations of SLC19A1 80G>A with NSCL/P risk were assessed by calculating the pooled odds ratios (ORs) and 95% confidence intervals (CIs) by meta-analyses.

METHODS

Following the PRISMA guidelines, a meta-analysis was conducted on 10 studies assessing the NSCL/P risk associated with SLC19A1 80G>A variant. To ascertain the degree of relationship between the SLC19A1 80G>A genetic variant and the risk of NSCL/P, data were analyzed in allelic, recessive and dominant genetic models. CI of OR for each study and the pooled data were obtained. All statistical analyses were conducted utilizing the MetaGenyo software tool, which integrates the adjustment of P values for multiple testing through the Bonferroni method.

RESULTS

The pooled analysis showed that SLC19A1 80G>A variant significantly increased the NSCL/P risk in the allelic model (OR 1.39; 95% CI 1.00-1.92), recessive model (OR 1.37; 95% CI 1.03-1.82) and dominant models (OR 1.7; 95% CI 1.05-2.90). Publication bias was not observed.

CONCLUSIONS

This study supports that the SLC19A1 80G>A genetic variant is associated with NSCL/P risk.

MTHFR 677C>T and 1298A>C Variants in Mothers of Infants with Down Syndrome from Western Mexico

Background: Several studies in mothers of infants with Down syndrome (DS) (MoIDS) have suggested that the 677C>T and 1298A>C variants of the 5,10-methylentetrahydrofolate reductase (MTHFR) gene can increase the risk of having a child with DS. Aim: This study aimed to evaluate the MTHFR 677C>T and 1298A>C variants as potential maternal risk factors for DS. Materials and Methods: Using TaqMan allelic discrimination assay, we genotyped 95 MoIDS and 164 control mothers from western Mexico. Data were analyzed using logistic regression analysis. Results: We found that MoIDS had a significantly higher risk for the MTHFR 677TT genotype (adjusted odds ratio [aOR] = 3.4, 95% confidence interval [95% CI]: 1.1-10.6), and the MTHFR 677T allele (aOR = 1.5, 95% CI: 1.0-2.3), particularly in MoIDS <35 years of age. Conclusions: Our findings indicate that the presence of the 677TT genotype and 677T allele of the MTHFR 677C>T variant are maternal risk factors for DS in Mexican MoIDS.

Maternal MTHFR 677C>T, 1298A>C gene polymorphisms and risk of offspring aneuploidy

OBJECTIVE

The objective was to investigate the association between maternal methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms, crucial for DNA methylation, and risk of offspring aneuploidy.

METHODS

MTHFR gene polymorphisms 677C>T and 1298A>C were determined by polymerase chain reaction based method, in 163 women with offspring aneuploidy and 155 women with healthy children. Five genetic models were used to assess risk, according to the type of aneuploidy and the age of women at conception.

RESULTS

MTHFR 677TT genotype and T allele were significantly more prevalent among women with offspring aneuploidy, with an increased risk of aneuploidy demonstrated under a recessive (OR 3.499), homozygote (OR 3.456) and allele contrast model (OR 1.574). The more prominent association was found with sex chromosome aneuploidies and trisomy 13/18, and also in women ≤35 years at conception. No association was observed between 1298A>C polymorphism and risk of offspring aneuploidy, although synergistic effect of two polymorphisms increase the risk of aneuploidy, primarily amplifying the 677T allele effects (p<0.001).

CONCLUSION

Maternal MTHFR 677C>T gene polymorphism, alone or in combination with another 1298A>C polymorphism, appears to be a substantial risk factor for offspring aneuploidy in Montenegro population, especially for sex chromosome aneuploidies and trisomy 13/18, and among younger women. This article is protected by copyright. All rights reserved.

Genetic polymorphisms in folate metabolism as risk for Down syndrome in the southern China

OBJECTIVE

To assess the association between maternal gene polymorphisms of the enzymes involved in folate metabolism and the risk of having a Down syndrome (DS) offspring in southern China mothers.

METHODS

Gene polymorphisms in folate metabolizing and the levels of homocysteine (HCY) were analyzed in 84 southern China mothers with DS babies (the case group) and 120 healthy mothers (the control group). Methylenetetrahydrofolate reductase (MTHFR) C677T (rs1801133) and A1298C (rs1801131), methionine synthase (MTR) A2756G (rs1805087), and methionine synthase reductase (MTRR) A66G (rs1801394) were studied.

RESULTS

We found no significant differences (p > .05) in the frequencies of four genetic polymorphisms between the two groups. We found gene-gene interactions had a 1.997-fold increased risk in MTHFR 677 CT with MTR AA (OR: 1.997, 95% CI: 1.038-3.841, p = .038) and a 2.588-fold increased risk in MTHFR 677 CT with MTRR AG (OR: 2.588, 95% CI: 1.111-6.031, p = .028) in the case group than control. The levels of HCY were significantly higher in MTHFR 677 TT than MTHFR 677 CC in the case group (TT 17.2167±5.1051, CC 12.1969±5.0299, F = 2.194, p < .05), and it was significantly higher in MTHFR 677 TT in the case group than control (TT 17.2167±5.1051 in the case group, TT 10.2286±1.4373 in the control group, F = 2.546, p < .05).

CONCLUSION

These results suggest that genetic polymorphisms involved in folate metabolism may have population specificity in determining the susceptibility of having DS offsprings. The gene-nutrition, gene-gene interactions and ethnicity are important variables to be considered in periconceptional nutritional supplementation and antenatal care for reducing the risk of DS babies.