Deep sequencing study of the MTHFR gene to identify variants associated with myelomeningocele
Chiamaka N Aneji1, Hope Northrup, Kit Sing Au
1Neonatal-Perinatal Medicine, Department of Pediatrics, University of Texas Houston Health Science Center, Houston, Texas, USA.
Introduction:
Neural tube defects (NTDs) are congenital anomalies caused by a combination of genetic and environmental influences. A defect below the head region resulting in protuberance of meninges and nervous tissue is termed myelomeningocele (MM). MM, the most common NTD compatible with survival, occurs in approximately 1 in 1000 births worldwide. Maternal preconceptional and periconceptional folate supplementation reduces the risk of NTDs by up to 70%. A key enzyme in folate metabolism is 5, 10-methylene-tetrahydrofolate reductase (MTHFR).
Objectives:
Sequence the 12 exons of the MTHFR gene among 96 subjects with MM to identify variants potentially contributing to the disease trait.
Methods:
Exons were amplified by polymerase chain reaction, and the products were sequenced with the Sanger method to reveal sequence variants compared to MTHFR reference sequences. Association of variants was examined by Fisher's test.
Results:
A novel variant c.171+3G>T was identified in intron 1 in one affected subject. The variant was not found in the subject's unaffected mother's DNA, and the unaffected father's DNA was unavailable. We found significant differences in allele frequencies for seven SNPs in MM subjects compared with ethnically matched reference populations reported in the single nucleotide polymorphism database.
Conclusion:
We identified a novel variant c.171+3G>T in the MTHFR gene that potentially affects splicing in an affected subject. In addition, we observed five SNPs (rs13306561, rs2274976, rs2066462, rs12121543, and rs1476413) in the MTHFR gene not previously shown to associate with MM. The current study provides additional evidence that multiple variations in the MTHFR gene are associated with MM.
Insights
Researchers sequenced the MTHFR gene in 96 myelomeningocele (MM) patients, identifying a novel variant potentially impacting splicing. This study highlights MTHFR gene variations
Area of Science:
- Genetics
- Developmental Biology
- Medical Research
Background:
- Neural tube defects (NTDs) are birth defects influenced by genetics and environment.
- Myelomeningocele (MM) is the most common NTD compatible with survival, affecting ~1 in 1000 births.
- Maternal folate intake significantly reduces NTD risk, implicating folate metabolism enzymes like MTHFR.
Purpose of the Study:
- To sequence all 12 exons of the MTHFR gene in 96 subjects with MM.
- To identify novel genetic variants in the MTHFR gene associated with MM.
- To investigate the role of MTHFR gene variations in the etiology of myelomeningocele.
Main Methods:
- Polymerase chain reaction (PCR) amplification of MTHFR gene exons.
- Sanger sequencing of amplified MTHFR gene products.
- Fisher's exact test to analyze the association of identified variants with MM.
Main Results:
- A novel MTHFR gene variant (c.171+3G>T) was identified in the intron 1 of one MM subject.
- Significant differences in allele frequencies for seven single nucleotide polymorphisms (SNPs) were observed in MM subjects compared to reference populations.
- Five previously unreported SNPs (rs13306561, rs2274976, rs2066462, rs12121543, rs1476413) in the MTHFR gene showed association with MM.
Conclusions:
- A novel MTHFR variant (c.171+3G>T) potentially affects mRNA splicing in an MM patient.
- Multiple MTHFR gene variations, including five novel associations, are linked to myelomeningocele.
- This research reinforces the association between MTHFR gene polymorphisms and MM risk.
