scholarly journals Genetic variation in genes of folate metabolism and neural-tube defect risk

2006 ◽  
Vol 65 (2) ◽  
pp. 204-215 ◽  
Author(s):  
Ivon J. M. van der Linden ◽  
Lydia A. Afman ◽  
Sandra G. Heil ◽  
Henk J. Blom
Keyword(s):  
Genetic Variation ◽  
Neural Tube ◽  
Methylenetetrahydrofolate Reductase ◽  
Mthfr Gene ◽  
Folate Metabolism ◽  
Nucleotide Polymorphism ◽  
Folate Transport ◽  
Single Nucleotide ◽  
Genes Encoding ◽  
B Vitamin

Neural-tube defects (NTD) are common congenital malformations that can lead to severe disability or even death. Periconceptional supplementation with the B-vitamin folic acid has been demonstrated to prevent 50–70% of NTD cases. Since the identification of the first genetic risk factor of NTD, the C677T single-nucleotide polymorphism (SNP) in the methylenetetrahydrofolate reductase (MTHFR) gene, and the observation that elevated plasma homocysteine levels are associated with NTD, research has focused on genetic variation in genes encoding for enzymes of folate metabolism and the closely-related homocysteine metabolism. In the present review relevant SNP in genes that code for enzymes involved in folate transport and uptake, the folate cycles and homocysteine metabolism are summarised and the importance of these SNP discussed in relation to NTD risk.

scholarly journals Single Nucleotide Polymorphism in SMAD7 and CHI3L1 and Colorectal Cancer Risk

2018 ◽  
Vol 2018 ◽  
pp. 1-23 ◽  
Author(s):  
Amal Ahmed Abd El-Fattah ◽  
Nermin Abdel Hamid Sadik ◽  
Olfat Gamil Shaker ◽  
Amal Mohamed Kamal
Keyword(s):  
Colorectal Cancer ◽  
Genetic Variation ◽  
Sequence Variation ◽  
Regulatory Protein ◽  
Nucleotide Polymorphisms ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
The Third ◽  
Common Cancer ◽  
Cancer Initiation

Colorectal cancer (CRC) is one of the leading cancers throughout the world. It represents the third most common cancer and the fourth in mortality. Most of CRC are sporadic, arise with no known high-penetrant genetic variation and with no previous family history. The etiology of sporadic CRC is considered to be multifactorial and arises from the interaction of genetic variants of low-penetrant genes and environmental risk factors. The most common well-studied genetic variation is single nucleotide polymorphisms (SNPs). SNP arises as a point mutation. If the frequency of the sequence variation reaches 1% or more in the population, it is referred to as polymorphism, but if it is lower than 1%, the allele is typically considered as a mutation. Lots of SNPs have been associated with CRC development and progression, for example, genes of TGF-β1 and CHI3L1 pathways. TGF-β1 is a pleiotropic cytokine with a dual role in cancer development and progression. TGF-β1 mediates its actions through canonical and noncanonical pathways. The most important negative regulatory protein for TGF-β1 activity is termed SMAD7. The production of TGF-βcan be controlled by another protein called YKL-40. YKL-40 is a glycoprotein with an important role in cancer initiation and metastasis. YKL-40 is encoded by the CHI3L1 gene. The aim of the present review is to give a brief introduction of CRC, SNP, and examples of some SNPs that have been documented to be associated with CRC. We also discuss two important signaling pathways TGF-β1 and CHI3L1 that influence the incidence and progression of CRC.

Utilizing Genomic DNA Purified From Clotted Blood Samples for Single Nucleotide Polymorphism Genotyping

2002 ◽  
Vol 126 (3) ◽  
pp. 266-270
Author(s):  
Karissa K. Adkins ◽  
Daniel A. Strom ◽  
Thomas E. Jacobson ◽  
Cara R. Seemann ◽  
Darin P. O'Brien ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Methylenetetrahydrofolate Reductase ◽  
Factor V ◽  
Single Nucleotide Polymorphism Genotyping ◽  
Nucleotide Polymorphism ◽  
High Quality ◽  
Genetic Tests ◽  
Single Nucleotide ◽  
Blood Samples ◽  
Clinical Laboratories

Abstract Context.—Linking single nucleotide polymorphisms to disease etiology is expected to result in a substantial increase in the number of genetic tests available and performed at clinical laboratories. Whole blood serves as the most common DNA source for these tests. Because the number of blood samples rises with the number of genetic tests performed, alternative DNA sources will become important. One such alternative source is clotted blood, a by-product of serum extraction. Efficiently using an already procured blood sample would limit the overall number of samples processed by clinical laboratories. Objective.—To determine if DNA purified from clotted blood can be effectively used for single nucleotide polymorphism genotyping. Design.—DNA was purified from the clotted blood of 15 donors. Single nucleotide polymorphism genotyping for the methylenetetrahydrofolate reductase and factor V Leiden mutations was performed with each DNA sample by 2 independent methods. Results.—High-quality DNA was obtained from each of the 15 individual clotted blood samples as demonstrated by UV spectrophotometric analysis, gel electrophoresis, and polymerase chain reaction amplification. The DNA was used successfully to obtain genotype data from both the methylenetetrahydrofolate reductase and factor V single nucleotide polymorphism assays for all samples tested. Conclusions.—Clotted blood is a clinically abundant sample type that can be used as a source of high-quality DNA for single nucleotide polymorphism genotyping.

scholarly journals The distinctive geographic patterns of common pigmentation variants at the OCA2 gene

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kenneth K. Kidd ◽  
Andrew J. Pakstis ◽  
Michael P. Donnelly ◽  
Ozlem Bulbul ◽  
Lotfi Cherni ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Oculocutaneous Albinism ◽  
Selection Effects ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Eye Color ◽  
Geographic Patterns ◽  
Population Genetic Variation ◽  
Oca2 Gene

Abstract Oculocutaneous Albinism type 2 (OCA2) is a gene of great interest because of genetic variation affecting normal pigmentation variation in humans. The diverse geographic patterns for variant frequencies at OCA2 have been evident but have not been systematically investigated, especially outside of Europe. Here we examine population genetic variation in and near the OCA2 gene from a worldwide perspective. The very different patterns of genetic variation found across world regions suggest strong selection effects may have been at work over time. For example, analyses involving the variants that affect pigmentation of the iris argue that the derived allele of the rs1800407 single nucleotide polymorphism, which produces a hypomorphic protein, may have contributed to the previously demonstrated positive selection in Europe for the enhancer variant responsible for light eye color. More study is needed on the relationships of the genetic variation at OCA2 to variation in pigmentation in areas beyond Europe.

scholarly journals The correlation between methylenetetrahydrofolate reductase gene 677C > T polymorphism and fetal congenital defects: A meta-analysis

Pteridines ◽  
2020 ◽  
Vol 31 (1) ◽  
pp. 9-17
Author(s):  
Dexia Li ◽  
Enxia Wang ◽  
Xia Gao ◽  
Ping Li
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Publication Bias ◽  
Methylenetetrahydrofolate Reductase ◽  
Meta Analysis ◽  
Random Effect ◽  
Congenital Defects ◽  
Nucleotide Polymorphism ◽  
Case Control Studies ◽  
Single Nucleotide ◽  
Increased Risk

AbstractObjective To investigate the correlation between the methylenetetrahydrofolate reductase (MTHFR) gene 677C> T polymorphism and fetal congenital defects.Method Original studies relevant to the MTHFR gene 677C>T single nucleotide polymorphism and fetal congenital defects were systematically searched in the electronic databases of Medline, EMBSE and China National Knowledge Infrastructure (CNKI). All relevant publications were screened for inclusion in the present work. The correlation between the MTHFR gene 677C > T single nucleotide polymorphism and the occurrence of fetal congenital defects was expressed as an odds ratio (OR) and its 95% confidence interval (95% CI). Publication bias was assessed by Begg’s funnel plot and Egger’s line regression test.Results Nineteen case-control studies were ultimately included in the present meta-analysis. The pooled results indicated that the general risk of fetal congenital defects was significantly elevated in subjects with the 677T allele of the MTHFR gene in dominant (OR=1.07,95%CI:1.03-1.12, P<0.05), homozygous (OR=1.17,95%CI:1.06-1.30, P<0.05) and recessive genetic models (OR=1.16,95%CI:1.03-1.31, P<0.05) through the random effect method. However, significant publication bias was identified upon pooling the individual data and evaluating the correlation.Conclusion According to the present evidence, the MTHFR gene 677C>T single nucleotide polymorphism is correlated with poor pregnancy outcomes, and subjects with the T allele have an increased risk of developing general fetal congenital defects.

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