Single nucleotide polymorphisms and pregnancy complications
Moshe Hod, Vincenzo Berghella, Mary E. D'Alton, Gian Carlo Di Renzo, Eduard Gratacós, Vassilios Fanos in New Technologies and Perinatal Medicine, 2019
Genetic polymorphism is an existence of two or more different alleles in one locus in DNA, more often than it is expected, according to mutation frequency in a population. Both the mutation and polymorphism are a qualitative and/or quantitative change in the genetic material. SNPs are point mutations, like insertion, deletion, or substitution of one of the nucleotides in a coding or uncoding DNA sequence. These are single-letter nucleotide changes that occur in 1% or more of the population. There are 12–15 million of such variants that have been meticulously catalogued by the human genome project in the publicly available database called dbSNP (http://www.ncbi.nlm.nih.gov/projects/SNP). A wide range of methods of finding polymorphisms is now available, like a genome-wide association study (GWAS) or genome-wide linkage study (GWLS). One study reported the results of the GWAS in which, as the first, a risk locus for preeclampsia on chromosome 2q14, near the inhibin ß B (INHBB) gene was identified. In that study, researchers had successfully genotyped 648,175 SNPs in 538 preeclampsia cases and 540 normal pregnancy controls with the usage of the Illumina OmniExpress-12 BeadChip (5).
Detection Techniques for Single Nucleotide Polymorphisms
Attila Lorincz in Nucleic Acid Testing for Human Disease, 2016
What distinguishes SNPs from other forms of genetic polymorphism is that the alleles at an SNP locus differ in DNA sequence by a single base. Although it is theoretically possible for an SNP locus to be tetra-allelic, the vast majority of SNPs have only two alleles. Curiously, roughly two thirds of human SNPs involve a single nucleotide substitution of a T for a C (Figure 6.2), probably arising through a de-amination mechanism known to occur frequently at CpG dinucle-otides.3 The allele with a higher frequency is termed the major allele; the other is designated the minor allele. Because the human genome is diploid in nature, an individual can be either homozygous (having two copies of the same allele at an SNP locus) or heterozygous (having one copy of each). The particular combination of alleles that an individual has at a particular locus is called a genotype.
Current and Potential Applications of Pharmacogenetics and Pharmacogenomics
John Y. M. Koo, Ethan C. Levin, Argentina Leon, Jashin J. Wu, Alice B. Gottlieb in Moderate to Severe Psoriasis, 2014
Psoriasis is a common, chronic skin disease affecting approximately 2%–3% of American adults [1]. The disease not only affects the physical health of patients but can also lead to substantial impairment of psychosocial well-being and overall quality of life. Furthermore, psoriasis represents a significant financial cost for patients and the overall health care system; the annual healthcare costs related to psoriasis are estimated to be US$11.3 billion [2]. The treatment options for psoriasis are manifold; however, none have proven to be universally remittive [3]. Why certain therapeutics are effective in some patients and ineffective in others is a question that has led some researchers to turn to the field of pharmacogenetics. Pharmacogenetic studies may identify genetic polymorphisms that can affect drug efficacy and/or toxicity among individuals.
Relationship between genetic polymorphism of MTHFR C677T and lower extremities deep venous thrombosis
Published in Hematology, 2019
Jiasheng Xu, Kexin Li, Weimin Zhou
Polymorphism refers to there are more than two genotypes in the same genetic loci in random mating population. In the population, the difference in the genetic nucleotide sequence in individuals is called genetic polymorphism. This kind of polymorphism can be divided into two categories, the DNA site polymorphism and DNA length polymorphism. In the past, genetic polymorphism analysis mostly used restriction fragment length polymorphism, SSCP, polymerase chain reaction (PCR), DNA sequencing, PCR oligonucleotide probe hybridization (PCR-SSO) method and sequence-specific oligonucleotide method (SSO) or other methods. The above method has the disadvantages of high technical requirements, complicated operation, expensive instruments, reagents required and long time for typing detection, which is not conducive to popularization in the laboratory. PCR-SSP utilizes Taq enzyme for the lack of 3′-5′ exonuclease activity. Sequence-specific primers (SSPs) and template DNAs are designed. The extension by Taq enzyme is blocked if bases are not complementary because of the failure in the formation of 3′, 5′ phosphodiester bond. then, the alleles of HLA were analyzed by gel electrophoresis amplification. The specificity of the duplicated product by the PCR-SSP method can be accurate to the difference in one base, and the amplified product can be analyzed by agarose gel electrophoresis. It has the characteristics of high resolution, strong specificity, simple technique, rapidness, easy application and promotion. Therefore, the PCR-SSP method was used for genetic polymorphism detection in this experiment.
Genetic polymorphisms for BDNF, COMT, and APOE do not affect gait or ankle motor control in chronic stroke: A preliminary cross-sectional study
Published in Topics in Stroke Rehabilitation, 2021
Rehab Aljuhni, Brice T. Cleland, Stephen Roth, Sangeetha Madhavan
There is much inter-individual variability in functional recovery after stroke.5,6 For example, motor recovery can vary from minimal to full recovery, making it difficult to predict with biomarkers. Genetic polymorphisms, frequently termed single nucleotide polymorphisms (SNP), are variations involving a change of nucleic acids in DNA sequence at one or more positions that may affect the function and expression of the gene. In other words, SNPs are DNA variations that (depending on the location) may affect gene expression, protein production, and bodily function. Many SNPs have no discernible effects, but others may explain interindividual differences in bodily functions, including functional recovery after stroke. Previous studies have suggested that polymorphisms of genes that encode brain-derived neurotrophic factor (BDNF), apolipoprotein E (APOE), and catechol-O-methyltransferase (COMT) influence functional recovery, cognitive and motor learning, and capacity for neuroplasticity in individuals with and without neurological impairment.7,8 It is unclear whether these polymorphisms influence recovery of walking and ankle motor control in chronic stroke.
The impact of leptin and its receptor polymorphisms on type 1 diabetes in a population of northwest Iran
Published in Annals of Human Biology, 2022
Parviz Azimnasab-sorkhabi, Maryam Soltani-asl, José Roberto Kfoury, Petra Algenstaedt, Hakan Farzin Mehmetzade, Yashar Hashemi Aghdam
Genetic polymorphisms have the potential to support or even cause phenotypic diversities among people such as disease risk and medication responses. Characterisation of genetic polymorphisms that regulate gene expression and protein function may assist in the recognition of various variants (Jin et al. 2018). Several studies have revealed associations between polymorphisms and diabetes in different populations including the Iranian population. For instance, recently, it has been shown that in the Iranian population NeuroD1 Ala45Thr polymorphism is significantly associated with T1D (Soltani Asl et al., 2020). Importantly, leptin (LEP) and leptin receptor (LEPR) genes are potential candidates to contribute to the pathophysiology of diabetes, obesity, metabolic syndrome, and cancer (Nesrine et al. 2018; Cheng et al. 2020). The LEP is an adipocyte-derived peptide hormone and plays several important roles in human physiology (Hussain et al. 2015; Yan et al. 2016). Therefore, the LEP G2548A and LEPR Q223R polymorphisms are potential targets to further studies at the genetic level to expand our knowledge regarding involved mechanisms in diabetes.
Related Knowledge Centers
- Allele
- Arachidonic Acid
- Cytosine
- Thymidine
- Stroke
- Hypertension
- Eicosanoid
- Gene
- Locus
- 20-Hydroxyeicosatetraenoic Acid