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Ashfaq F, Aljaadi AM, Salaka AS, Noorwali EA, Khatoon F, Khan MI. Comparison of TCN-2 (776C>G) Gene Polymorphism and Vitamin B12 Status with Different Body Mass Index among Saudi Adults. Life (Basel) 2023; 13:life13051185. [PMID: 37240829 DOI: 10.3390/life13051185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/10/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
BACKGROUND Overweight and obesity (OO) are significant public health issues, and many elements, including genetics, epigenetics, sedentary lifestyle, comorbid conditions, psychological and environmental pressures, have been linked to OO. More than 2 billion people are presently impacted by the global obesity epidemic, which is still advancing relentlessly. It is a significant public health concern and a major contributor to healthcare costs, because it increases the chance of developing conditions such as heart disease, stroke, type 2 diabetes, and chronic kidney disease (CKD). Using the ranges of 18.5-25 for normality, 25-30 for overweight, and 30 for obesity, BMI (in kg/m2) is used to identify obesity. Vitamin deficiency is one of the causative factors associated with the increasing trend of obesity. Altered vitamin B12 status is a multifactorial trait; changes in B12 status are produced by several single nucleotide polymorphisms (SNPs) in various genes that interact with the environment. They also support coordinated efforts to alter the built environment that is causing the obesity pandemic. Therefore, the present study aimed to evaluate the TCN-2 (776C>G) gene alteration and vitamin B12 levels with respect to different body mass index, as well as associating BMI with other biochemical parameters. METHODS 250 individuals were involved in the study; among them, 100 were in the healthy weight range category (BMI: 18.5 to <25 kg/m2), 100 were overweight (BMI: 25.0 to <30 kg/m2), and 50 were obese (BMI: >30 kg/m2). Participants visited during the screening program were subjected to blood pressure measurement, and further peripheral blood samples were drawn from all the participants in plain as well as in EDTA vials for biochemical (lipid profile and vitamin B12 level) analysis and single nucleotide polymorphism studies. Extracted DNA from whole blood collected in EDTA vials using kit protocol was used for genotyping by PCR-RFLP. RESULTS The levels of systolic (p < 0.0001) and diastolic blood pressures (p < 0.0001), HDL (p < 0.0001), LDL (p = 0.04), TG (p < 0.0001), cholesterol (p < 0.0001), and VLDL (p < 0.0001) showed significant differences between healthy controls, overweight, and obese groups. The healthy control TCN-2 (776C>G) genotypes were compared with those of overweight and obese participants, and compared to the healthy controls it was observed that overweight (p = 0.01) and obese (p = 0.002) subjects had significant differences in TCN-2 (776C>G) genotypes. For genotypes CG and GG, the odds ratio was 1.61 (0.87-2.95; p = 0.12), and 3.81 (1.47-9.88; p = 0.005) for overweight participants, respectively, and obese participants' calculated odds ratios were 2.49 (1.16-5.36; p = 0.01) and 5.79 (1.93-17.35; p = 0.001), respectively. The relative risk for genotypes CG and GG, was 1.25 (0.93-1.68; p = 0.12), 2.17 (1.12-4.17; p = 0.02) for overweight participants, while the obese participants' calculated relative risks were 1.31 (1.03-1.68; p = 0.01) and 2.02 (1.12-3.65; p = 0.001), respectively. Vitamin B12 levels were analyzed, and it was observed that a significant difference existed among overweight (305.5 pmol/L, p < 0.0001) and obese patients (229 pmol/L, p < 0.0001), respectively, as compared to healthy controls (385.5 pmol/L). Correlation analysis showed a significant association of vitamin B12 level with TG, cholesterol and VLDL; it showed a negative correlation, suggesting that decreases in B12 levels may impact the lipid profile. CONCLUSION The study concluded that a predisposition to the GG genotype of TCN-2 gene polymorphism (776C>G) may increase susceptibility to obesity and the related complications, and higher odds and relative risk for the GG genotype may increase the risk of having obesity and further related complications. Lower vitamin B12 levels were linked with obesity and overweight, and impaired lipid parameters suggested that lower vitamin B12 may impact the altered lipid profile.
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Affiliation(s)
- Fauzia Ashfaq
- Department of Clinical Nutrition, College of Applied Medical Sciences, Jazan University, Jazan 45142, Saudi Arabia
| | - Abeer M Aljaadi
- Clinical Nutrition Department, Faculty of Applied Medical Sciences, Umm Al-Qura University, Makkah 21955, Saudi Arabia
| | - Afnan S Salaka
- Laboratory Medicine Department, Faculty of Applied Medical Sciences, Umm Al-Qura University, Makkah 21955, Saudi Arabia
| | - Essra A Noorwali
- Clinical Nutrition Department, Faculty of Applied Medical Sciences, Umm Al-Qura University, Makkah 21955, Saudi Arabia
| | - Fahmida Khatoon
- Department of Biochemistry, College of Medicine, University of Hail, Hail P.O. Box 2440, Saudi Arabia
| | - Mohammad Idreesh Khan
- Department of Clinical Nutrition, College of Applied Health Sciences in Ar Rass, Qassim University, Ar Rass 51921, Saudi Arabia
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Whole exome sequencing, a hypothesis-free approach to investigate recurrent early miscarriage. Reprod Biomed Online 2021; 42:789-798. [PMID: 33658156 DOI: 10.1016/j.rbmo.2021.01.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 12/19/2020] [Accepted: 01/12/2021] [Indexed: 12/11/2022]
Abstract
RESEARCH QUESTION Are there genetic determinants shared by unrelated women with unexplained recurrent early miscarriage (REM)? DESIGN Thirty REM cases and 30 controls were selected with extreme phenotype among women from Eastern Brittany (France), previously enrolled in an incident case-control study on thrombophilic mutations. Cases and controls were selected based on the number of early miscarriages or live births, respectively. Peripheral blood was collected for DNA extraction at initial visit. The burden of low-frequency variants in the coding part of the genes was compared using whole exome sequencing (WES). RESULTS Cases had 3 to 17 early miscarriages (20 cases: ≥5 previous losses). Controls had 1 to 4 live births (20 controls: ≥3 previous live births) and no miscarriages. WES data were available for 29 cases and 30 controls. A total of 209,387 variants were found (mean variant per patient: 59,073.05) with no difference between groups (P = 0.68). The top five most significantly associated genes were ABCA4, NFAM1, TCN2, AL078585.1 and EPS15. Previous studies suggest the involvement of vitamin B12 deficiency in REM. TCN2 encodes for vitamin B12 transporter into cells. Therefore, holotranscobalamin (active vitamin B12) was measured for both cases and controls (81.2 ± 32.1 versus 92.9 ± 34.3 pmol/l, respectively, P = 0.186). Five cases but no controls were below 50 pmol/l (P = 0.052). CONCLUSIONS This study highlights four new genes of interest in REM, some of which belong to known networks of genes involved in embryonic development (clathrin-mediated endocytosis and ciliary pathway). The study also confirms the involvement of TCN2 (vitamin B12 pathway) in the early first trimester of pregnancy.
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Association of single nucleotide polymorphisms of MTHFR, TCN2, RNF213 with susceptibility to hypertension and blood pressure. Biosci Rep 2020; 39:221446. [PMID: 31815282 PMCID: PMC6923352 DOI: 10.1042/bsr20191454] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 11/28/2019] [Accepted: 12/07/2019] [Indexed: 12/19/2022] Open
Abstract
Methylenetetrahydrofolate reductase gene (MTHFR), transcobalaminII (TCN2) and ring finger protein 213 (RNF213) are related to homocysteine (Hcy) level and are of great significance for hypertension. We aimed to evaluate the associations of MTHFR (rs1801133, rs1801131, rs9651118), TCN2 (rs117353193) and RNF213 (rs9916351) with hypertension and blood pressure (BP). A total of 953 patients with hypertension and 1103 controls were enrolled. Genotyping was performed by Taqman. Logistic regression analysis indicated that A allele of TCN2 rs117353193 under the dominant model had a significantly protective effect (P=0.045) after adjustment, which showed that AA+GA genotype has a lower risk than GG. Additionally, the average diastolic BP (DBP) (P=0.044) and mean arterial pressure (MAP) (P=0.035) levels were significantly different between genotypes of RNF213 rs9916351. Further pairwise comparison showed that the average systolic BP (SBP) level of the TT genotype carriers were significantly higher than in CC (P=0.024), and the average DBP and MAP levels of the TT genotype carriers were higher than in CT (P=0.044, P=0.012, respectively) and CC (P=0.048, P=0.010, respectively). In the recessive model, the average SBP (P=0.043), DBP (P=0.018) and MAP (P=0.017) levels with the TT genotype carriers were significantly higher than in CT+CC. Multiple linear regression analysis suggested that RNF213 rs9916351 in the recessive model had significant effects on SBP (P=0.025), DBP (P=0.017) and MAP (P=0.010) as a risk factor. However, no associations were observed between MTHFR and hypertension. TCN2 rs117353193 might serve as a protective factor in hypertension, and RNF213 rs9916351 might be a risk factor that is linked to increase BP level in Northeast Chinese population.
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Park HS, Kim JO, An HJ, Ryu CS, Ko EJ, Kim YR, Ahn EH, Lee WS, Kim JH, Kim NK. Genetic polymorphisms of the cobalamin transport system are associated with idiopathic recurrent implantation failure. J Assist Reprod Genet 2019; 36:1513-1522. [PMID: 31123954 DOI: 10.1007/s10815-019-01455-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/16/2019] [Indexed: 12/15/2022] Open
Abstract
PURPOSE Vitamin B12 (cobalamin, Cbl) plays a role in the recycling of folate, which is important in pregnancy. Transcobalamin II (TCN2) and transcobalamin receptor (TCblR) proteins are involved in the cellular uptake of Cbl. TCN2 binds Cbl in the plasma, and TCblR binds TCN2-Cbl at the cell surface. Therefore, we investigated the potential association between polymorphisms in Cbl transport proteins, TCN2 and TCblR, and recurrent implantation failure (RIF) susceptibility. METHODS The genotypes of TCN2 67A>G, TCN2 776C>G, and TCblR 1104C>T were determined for RIF patients and healthy controls using a polymerase chain reaction restriction fragment length polymorphism assay. Additionally, statistical analysis was performed to compare the genotype frequencies between RIF patients and controls. RESULTS The TCN2 67 polymorphism AG type was associated with RIF risk. Some allele combinations that contained the TCN2 67 polymorphism G allele were associated with increased RIF risk, whereas other allele combinations that contained the TCblR 1104 polymorphism T alleles were associated with decreased RIF risk. In genotype combination analysis, two combinations containing the TCN2 67 polymorphism AG type were associated with RIF risk. CONCLUSION Our study showed that the polymorphisms of TCN2 and TCblR are associated with RIF and are potential genetic predisposing factors for RIF among Korean women. Additionally, our findings support a potential role for TCN2 and TCblR in RIF among Korean women. However, further studies are required to investigate the role of the polymorphisms in those proteins and RIF because the roles of the TCN2 and TCblR polymorphisms in RIF are not clear.
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Affiliation(s)
- Han Sung Park
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Jung Oh Kim
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Hui Jeong An
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Chang Soo Ryu
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Eun Ju Ko
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea
| | - Young Ran Kim
- Department of Obstetrics and Gynecology, CHA Bundang Medical Center, CHA University, 11, Yatap-ro 65beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Eun Hee Ahn
- Department of Obstetrics and Gynecology, CHA Bundang Medical Center, CHA University, 11, Yatap-ro 65beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Woo Sik Lee
- Fertility Center of CHA Gangnam Medical Center, CHA University, 566, Nonhyeon-ro, Gangnam-gu, Seoul, 06135, Republic of Korea
| | - Ji Hyang Kim
- Department of Obstetrics and Gynecology, CHA Bundang Medical Center, CHA University, 11, Yatap-ro 65beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea.
| | - Nam Keun Kim
- Department of Biomedical Science, College of Life Science, CHA University, 355, Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, Republic of Korea.
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Salinas M, Flores E, López-Garrigós M, Leiva-Salinas C. Vitamin B12 deficiency and clinical laboratory: Lessons revisited and clarified in seven questions. Int J Lab Hematol 2018; 40 Suppl 1:83-88. [PMID: 29741251 DOI: 10.1111/ijlh.12833] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 03/22/2018] [Indexed: 11/26/2022]
Abstract
The objective of this review article is to address the most frequently asked questions that pathologists and primary care physicians might face when dealing with a patient with suspicion of vitamin B12 deficiency. More specifically, the article mainly discusses the importance and prevalence of the deficit, how to recognize it, and the important role of a prompt diagnosis confirmation based on laboratory biomarkers for efficient replacement therapy.
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Affiliation(s)
- M Salinas
- Clinical Laboratory, Hospital Universitario de San Juan, San Juan de Alicante, Spain.,Department of Biochemistry and Molecular Pathology, Universidad Miguel Hernandez, Elche, Spain
| | - E Flores
- Clinical Laboratory, Hospital Universitario de San Juan, San Juan de Alicante, Spain.,Department of Clinic Medicine, Universidad Miguel Hernandez, Elche, Spain
| | - M López-Garrigós
- Clinical Laboratory, Hospital Universitario de San Juan, San Juan de Alicante, Spain
| | - C Leiva-Salinas
- Department of Clinical Radiology, University of Missouri Health, Columbia, MO, USA
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Hashemi M, Mokhtari M, Yazdani-Shahrbabaki V, Danesh H, Bizhani F, Taheri M. Evaluation of transcobalamin II rs1801198 and transcobalamin II receptor rs2336573 gene polymorphisms in recurrent spontaneous abortion. J OBSTET GYNAECOL 2018. [DOI: 10.1080/01443615.2017.1420045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Mohammad Hashemi
- Cellular and Molecular Research Center, Zahedan University of Medical Sciences, Zahedan, Iran
- Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Mojgan Mokhtari
- Department of Obstetrics and Gynecology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Vajiheh Yazdani-Shahrbabaki
- Department of Obstetrics and Gynecology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Hiva Danesh
- Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Fatemeh Bizhani
- Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Mohsen Taheri
- Genetics of Non-communicable Disease Research Center, Zahedan University of Medical Sciences, Zahedan, Iran
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Surendran S, Adaikalakoteswari A, Saravanan P, Shatwaan IA, Lovegrove JA, Vimaleswaran KS. An update on vitamin B12-related gene polymorphisms and B12 status. GENES AND NUTRITION 2018; 13:2. [PMID: 29445423 PMCID: PMC5801754 DOI: 10.1186/s12263-018-0591-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 01/23/2018] [Indexed: 12/12/2022]
Abstract
Background Vitamin B12 is an essential micronutrient in humans needed for health maintenance. Deficiency of vitamin B12 has been linked to dietary, environmental and genetic factors. Evidence for the genetic basis of vitamin B12 status is poorly understood. However, advancements in genomic techniques have increased the knowledge-base of the genetics of vitamin B12 status. Based on the candidate gene and genome-wide association (GWA) studies, associations between genetic loci in several genes involved in vitamin B12 metabolism have been identified. Objective The objective of this literature review was to identify and discuss reports of associations between single-nucleotide polymorphisms (SNPs) in vitamin B12 pathway genes and their influence on the circulating levels of vitamin B12. Methods Relevant articles were obtained through a literature search on PubMed through to May 2017. An article was included if it examined an association of a SNP with serum or plasma vitamin B12 concentration. Beta coefficients and odds ratios were used to describe the strength of an association, and a P < 0.05 was considered as statistically significant. Two reviewers independently evaluated the eligibility for the inclusion criteria and extracted the data. Results From 23 studies which fulfilled the selection criteria, 16 studies identified SNPs that showed statistically significant associations with vitamin B12 concentrations. Fifty-nine vitamin B12-related gene polymorphisms associated with vitamin B12 status were identified in total, from the following populations: African American, Brazilian, Canadian, Chinese, Danish, English, European ancestry, Icelandic, Indian, Italian, Latino, Northern Irish, Portuguese and residents of the USA. Conclusion Overall, the data analyzed suggests that ethnic-specific associations are involved in the genetic determination of vitamin B12 concentrations. However, despite recent success in genetic studies, the majority of identified genes that could explain variation in vitamin B12 concentrations were from Caucasian populations. Further research utilizing larger sample sizes of non-Caucasian populations is necessary in order to better understand these ethnic-specific associations.
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Affiliation(s)
- S Surendran
- 1Hugh Sinclair Unit of Human Nutrition, Department of Food and Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, PO Box 226, Whiteknights, Reading, RG6 6AP UK
| | - A Adaikalakoteswari
- 2Warwick Medical School - Population Evidence and Technologies, University of Warwick, Coventry, CV4 7AL UK.,3UK Academic Department of Diabetes and Metabolism, George Eliot Hospital, Nuneaton, UK
| | - P Saravanan
- 2Warwick Medical School - Population Evidence and Technologies, University of Warwick, Coventry, CV4 7AL UK.,3UK Academic Department of Diabetes and Metabolism, George Eliot Hospital, Nuneaton, UK
| | - I A Shatwaan
- 1Hugh Sinclair Unit of Human Nutrition, Department of Food and Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, PO Box 226, Whiteknights, Reading, RG6 6AP UK
| | - J A Lovegrove
- 1Hugh Sinclair Unit of Human Nutrition, Department of Food and Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, PO Box 226, Whiteknights, Reading, RG6 6AP UK
| | - K S Vimaleswaran
- 1Hugh Sinclair Unit of Human Nutrition, Department of Food and Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, PO Box 226, Whiteknights, Reading, RG6 6AP UK
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Hibbeln JR, SanGiovanni JP, Golding J, Emmett PM, Northstone K, Davis JM, Schuckit M, Heron J. Meat Consumption During Pregnancy and Substance Misuse Among Adolescent Offspring: Stratification of TCN2 Genetic Variants. Alcohol Clin Exp Res 2017; 41:1928-1937. [PMID: 28975627 DOI: 10.1111/acer.13494] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 08/29/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND Reducing meat consumption is often advised; however, inadvertent nutritional deficiencies during pregnancy may result in residual neurodevelopmental harms to offspring. This study assessed possible effects of maternal diets in pregnancy on adverse substance use among adolescent offspring. METHODS Pregnant women and their 13-year-old offspring taking part in a prospective birth cohort study, the Avon Longitudinal Study of Parents and Children (ALSPAC), provided Food Frequency Questionnaire data from which dietary patterns were derived using principal components analysis. Multivariable logistic regression models including potential confounders evaluated adverse alcohol, cannabis, and tobacco use of the children at 15 years of age. RESULTS Lower maternal meat consumption was associated with greater problematic substance use among 15-year-old offspring in dose-response patterns. Comparing never to daily meat consumption after adjustment, risks were greater for all categories of problem substance use: alcohol, odds ratio OR = 1.75, 95% CI = (1.23, 2.56), p < 0.001; tobacco use OR = 1.85, 95% CI = (1.28, 2.63), p < 0.001; and cannabis OR = 2.70, 95% CI = (1.89, 4.00), p < 0.001. Given the likelihood of residual confounding, potential causality was evaluated using stratification for maternal allelic variants that impact biological activity of cobalamin (vitamin B12) and iron. Lower meat consumption disproportionally increased the risks of offspring substance misuse among mothers with optimally functional (homozygous) variants (rs1801198) of the gene transcobalamin 2 gene (TCN2) which encodes the vitamin B12 transport protein transcobalamin 2 implicating a causal role for cobalamin deficits. Functional maternal variants in iron metabolism were unrelated to the adverse substance use. Risks potentially attributable to cobalamin deficits during pregnancy include adverse adolescent alcohol, cannabis, and tobacco use (14, 37, and 23, respectively). CONCLUSIONS Lower prenatal meat consumption was associated with increased risks of adolescent substance misuse. Interactions between TCN2 variant status and meat intake implicate cobalamin deficiencies.
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Affiliation(s)
- Joseph R Hibbeln
- Section on Nutritional Neurosciences, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| | - John Paul SanGiovanni
- Section on Nutritional Neurosciences, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland.,Georgetown University School of Medicine, Washington, District of Columbia
| | - Jean Golding
- School of Social and Community Based Medicine, University of Bristol, Bristol, United Kingdom
| | - Pauline M Emmett
- School of Social and Community Based Medicine, University of Bristol, Bristol, United Kingdom
| | - Kate Northstone
- School of Social and Community Based Medicine, University of Bristol, Bristol, United Kingdom
| | - John M Davis
- University of Illinois at Chicago, Chicago, Illinois
| | - Marc Schuckit
- University of California, San Diego, San Diego, California
| | - Jon Heron
- School of Social and Community Based Medicine, University of Bristol, Bristol, United Kingdom
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A missense mutation in TCN2 is associated with decreased risk for congenital heart defects and may increase cellular uptake of vitamin B12 via Megalin. Oncotarget 2017; 8:55216-55229. [PMID: 28903415 PMCID: PMC5589654 DOI: 10.18632/oncotarget.19377] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 06/29/2017] [Indexed: 12/05/2022] Open
Abstract
Deregulation of folate and vitamin B12 (VB12) metabolism contributes to the risk of congenital heart defects (CHDs). Transcobalamin (TCN2) is essential for transporting VB12 from blood to cells as TCN2-bound VB12 (holo-TC) is the only form for somatic cellular uptake. In this study, we performed an association study between common polymorphisms in 46 one carbon metabolism genes and CHD in 412 CHDs and 213 controls. Only two significant association signals in coding regions were identified: FTCD c.1470C>T & TCN2 c.230A>T. The only missense mutation, TCN2 c.230A>T, was further validated in 412 CHDs and 1177 controls. TCN2 c.230T is significantly associated with reduced CHD risk in North Chinese (odds ratio = 0.67, P = 4.62e-05), compared with the 230A allele. Interestingly, the mean level of plasma holo-TC in women with the TA genotype was 1.77-fold higher than that in women with the AA genotype. Further analysis suggested that c.230A>T enhanced the cellular uptake of holo-TC via the LRP2 receptor. Our results determined that a functional polymorphism in TCN2 contributes to the prevalence of CHDs. TCN2 c.230A>T is significantly associated with a reduced CHD risk, likely due to TCN2 c.230T improving the interaction between holo-TC and its LRP2 receptor.
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Association of ulcerative colitis with transcobalamin II gene polymorphisms and serum homocysteine, vitamin B12, and folate levels in Chinese patients. Immunogenetics 2017; 69:421-428. [DOI: 10.1007/s00251-017-0998-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 05/04/2017] [Indexed: 12/23/2022]
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Porter K, Hoey L, Hughes CF, Ward M, McNulty H. Causes, Consequences and Public Health Implications of Low B-Vitamin Status in Ageing. Nutrients 2016; 8:E725. [PMID: 27854316 PMCID: PMC5133110 DOI: 10.3390/nu8110725] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/26/2016] [Accepted: 11/09/2016] [Indexed: 12/11/2022] Open
Abstract
The potential protective roles of folate and the metabolically related B-vitamins (vitamins B12, B6 and riboflavin) in diseases of ageing are of increasing research interest. The most common cause of folate and riboflavin deficiencies in older people is low dietary intake, whereas low B12 status is primarily associated with food-bound malabsorption, while sub-optimal vitamin B6 status is attributed to increased requirements in ageing. Observational evidence links low status of folate and the related B-vitamins (and/or elevated concentrations of homocysteine) with a higher risk of degenerative diseases including cardiovascular disease (CVD), cognitive dysfunction and osteoporosis. Deficient or low status of these B-vitamins alone or in combination with genetic polymorphisms, including the common MTHFR 677 C → T polymorphism, could contribute to greater disease risk in ageing by causing perturbations in one carbon metabolism. Moreover, interventions with the relevant B-vitamins to optimise status may have beneficial effects in preventing degenerative diseases. The precise mechanisms are unknown but many have been proposed involving the role of folate and the related B-vitamins as co-factors for one-carbon transfer reactions, which are fundamental for DNA and RNA biosynthesis and the maintenance of methylation reactions. This review will examine the evidence linking folate and related B-vitamins with health and disease in ageing, associated mechanisms and public health implications.
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Affiliation(s)
- Kirsty Porter
- Northern Ireland Centre for Food and Health, Ulster University, Cromore Road, Coleraine BT52 1SA, UK.
| | - Leane Hoey
- Northern Ireland Centre for Food and Health, Ulster University, Cromore Road, Coleraine BT52 1SA, UK.
| | - Catherine F Hughes
- Northern Ireland Centre for Food and Health, Ulster University, Cromore Road, Coleraine BT52 1SA, UK.
| | - Mary Ward
- Northern Ireland Centre for Food and Health, Ulster University, Cromore Road, Coleraine BT52 1SA, UK.
| | - Helene McNulty
- Northern Ireland Centre for Food and Health, Ulster University, Cromore Road, Coleraine BT52 1SA, UK.
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Hannibal L, Lysne V, Bjørke-Monsen AL, Behringer S, Grünert SC, Spiekerkoetter U, Jacobsen DW, Blom HJ. Biomarkers and Algorithms for the Diagnosis of Vitamin B12 Deficiency. Front Mol Biosci 2016; 3:27. [PMID: 27446930 PMCID: PMC4921487 DOI: 10.3389/fmolb.2016.00027] [Citation(s) in RCA: 173] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/07/2016] [Indexed: 12/12/2022] Open
Abstract
Vitamin B12 (cobalamin, Cbl, B12) is an indispensable water-soluble micronutrient that serves as a coenzyme for cytosolic methionine synthase (MS) and mitochondrial methylmalonyl-CoA mutase (MCM). Deficiency of Cbl, whether nutritional or due to inborn errors of Cbl metabolism, inactivate MS and MCM leading to the accumulation of homocysteine (Hcy) and methylmalonic acid (MMA), respectively. In conjunction with total B12 and its bioactive protein-bound form, holo-transcobalamin (holo-TC), Hcy, and MMA are the preferred serum biomarkers utilized to determine B12 status. Clinically, vitamin B12 deficiency leads to neurological deterioration and megaloblastic anemia, and, if left untreated, to death. Subclinical vitamin B12 deficiency (usually defined as a total serum B12 of <200 pmol/L) presents asymptomatically or with rather subtle generic symptoms that oftentimes are mistakenly ascribed to unrelated disorders. Numerous studies have now established that serum vitamin B12 has limited diagnostic value as a stand-alone marker. Low serum levels of vitamin B12 not always represent deficiency, and likewise, severe functional deficiency of the micronutrient has been documented in the presence of normal and even high levels of serum vitamin B12. This review discusses the usefulness and limitations of current biomarkers of B12 status in newborn screening, infant and adult diagnostics, the algorithms utilized to diagnose B12 deficiency and unusual findings of vitamin B12 status in various human disorders.
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Affiliation(s)
- Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Vegard Lysne
- Department of Clinical Sciences, University of Bergen Bergen, Norway
| | | | - Sidney Behringer
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Sarah C Grünert
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Ute Spiekerkoetter
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Donald W Jacobsen
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Cleveland, OH, USA
| | - Henk J Blom
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
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Basak T, Garg G, Bhardwaj N, Tanwar VS, Seth S, Karthikeyan G, Sengupta S. Low holo-transcobalamin levels are prevalent in vegetarians and is associated with coronary artery disease in Indian population. Biomarkers 2016; 21:436-40. [DOI: 10.3109/1354750x.2016.1153718] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Trayambak Basak
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, Sukhdev Vihar, New Delhi, India
- Academy of Scientific & Innovative Research (AcSIR), CSIR-IGIB Campus, New Delhi, India
| | - Gaurav Garg
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, Sukhdev Vihar, New Delhi, India
| | - Nitin Bhardwaj
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, Sukhdev Vihar, New Delhi, India
| | - Vinay Singh Tanwar
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, Sukhdev Vihar, New Delhi, India
| | - Sandeep Seth
- Department of Cardiology, All India Institute of Medical Sciences, New Delhi, India
| | - Ganesan Karthikeyan
- Department of Cardiology, All India Institute of Medical Sciences, New Delhi, India
| | - Shantanu Sengupta
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, Sukhdev Vihar, New Delhi, India
- Academy of Scientific & Innovative Research (AcSIR), CSIR-IGIB Campus, New Delhi, India
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Quay TA, Schroder TH, Jeruszka-Bielak M, Li W, Devlin AM, Barr SI, Lamers Y. High prevalence of suboptimal vitamin B12 status in young adult women of South Asian and European ethnicity. Appl Physiol Nutr Metab 2015; 40:1279-86. [DOI: 10.1139/apnm-2015-0200] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Suboptimal vitamin B12 (B12) status has been associated with an increased risk of congenital anomalies, preterm birth, and childhood insulin resistance. South Asians – Canada’s largest minority group – and women of reproductive age are vulnerable to B12 deficiency. This study aimed to assess the prevalence of and factors associated with B12 deficiency and suboptimal B12 status in a convenience sample of young adult women of South Asian and European descent in Metro Vancouver. We measured serum B12, holotranscobalamin, plasma methylmalonic acid, red blood cell and plasma folate, and hematologic parameters in 206 nonpregnant, healthy women aged 19–35 years. Categorization for B12 status adhered to serum B12 cutoffs for deficiency (<148 pmol/L) and suboptimal B12 status (148–220 pmol/L). We collected demographic, lifestyle, and dietary intake data and conducted genotyping for common genetic variants linked to B-vitamin metabolism. The prevalence of deficiency and suboptimal B12 status were 14% and 20%, respectively. Serum vitamin B12 concentrations were negatively associated with oral contraceptive use and first-generation immigrant status, and positively with dietary B12 intake and B12 supplement use. The prevalence of B12 inadequacy in this sample of highly educated women is higher than in the general Canadian population. In light of maternal and fetal health risks associated with B12 inadequacy in early-pregnancy, practitioners should consider monitoring B12 status before and during early pregnancy, especially in immigrants and women with low dietary B12 intakes including non-users of vitamin supplements.
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Affiliation(s)
- Teo A.W. Quay
- Food Nutrition and Health, Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Theresa H. Schroder
- Food Nutrition and Health, Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Marta Jeruszka-Bielak
- Food Nutrition and Health, Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Wangyang Li
- Food Nutrition and Health, Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Angela M. Devlin
- Division of Endocrinology, Department of Pediatrics, University of British Columbia, British Columbia, Canada
- Child and Family Research Institute, Vancouver British Columbia, Canada
| | - Susan I. Barr
- Food Nutrition and Health, Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Yvonne Lamers
- Food Nutrition and Health, Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Child and Family Research Institute, Vancouver British Columbia, Canada
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Lahner E, Gentile G, Purchiaroni F, Mora B, Simmaco M, Annibale B. Single nucleotide polymorphisms related to vitamin B12 serum levels in autoimmune gastritis patients with or without pernicious anaemia. Dig Liver Dis 2015; 47:285-90. [PMID: 25681243 DOI: 10.1016/j.dld.2015.01.147] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 01/10/2015] [Accepted: 01/15/2015] [Indexed: 02/05/2023]
Abstract
BACKGROUND Autoimmune gastritis may present as pernicious anaemia arising from vitamin B12 malabsorption, but also with iron deficiency anaemia due to iron malabsorption. These different clinical presentations might have a genetic basis. Single nucleotide polymorphisms associated with vitamin B12 levels have not been investigated in autoimmune gastritis. AIMS To determine the frequency of single nucleotide polymorphisms related to vitamin B12 levels in autoimmune gastritis patients, with or without pernicious anaemia, compared to healthy controls. METHODS 14 single nucleotide polymorphisms associated with vitamin B12 levels were selected from literature. 83 autoimmune gastritis patients (43 with and 40 without pernicious anaemia) and 173 controls were enrolled. Genomic DNA was extracted from peripheral blood leukocytes. Genotyping was performed using Sequenom MALDI-TOF mass spectrometry iPLEX platform. RESULTS TCN2 (rs9606756) GG genotype, related with lower vitamin B12 levels, was found in 3 (3.6%) autoimmune gastritis patients (2 with pernicious anaemia), but in none of controls (p = 0.02). FUT6 (rs3760776) AA genotype was present in four (4.8%) autoimmune gastritis patients (all pernicious anaemia) and three (1.7%) controls (p = 0.007). CONCLUSION A genetic variant of TCN2 (rs9606756) related to lower vitamin B12 levels was more frequent in pernicious anaemia patients compared to controls, showing the plausibility of genetic factors determining the possible clinical manifestation of autoimmune gastritis.
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Affiliation(s)
- Edith Lahner
- Digestive and Liver Disease Unit, Department of Medical and Surgery Sciences and Translational Medicine, Sant'Andrea Hospital, Sapienza University Rome, Rome, Italy
| | - Giovanna Gentile
- Advanced Molecular Diagnostics Unit, Sant'Andrea Hospital, Rome, Italy
| | - Flaminia Purchiaroni
- Digestive and Liver Disease Unit, Department of Medical and Surgery Sciences and Translational Medicine, Sant'Andrea Hospital, Sapienza University Rome, Rome, Italy
| | - Barbara Mora
- Department of Pathology, Policlinico Umberto I, Medical School, Sapienza University Rome, Rome, Italy
| | - Maurizio Simmaco
- Advanced Molecular Diagnostics Unit, Sant'Andrea Hospital, Rome, Italy; Department of Neuroscience, Mental Health and Sense Organs, Faculty of Medicine and Psychology, Sapienza University Rome, Rome, Italy
| | - Bruno Annibale
- Digestive and Liver Disease Unit, Department of Medical and Surgery Sciences and Translational Medicine, Sant'Andrea Hospital, Sapienza University Rome, Rome, Italy.
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Cascalheira JF, Gonçalves M, Barroso M, Castro R, Palmeira M, Serpa A, Dias-Cabral AC, Domingues FC, Almeida S. Association of the transcobalamin II gene 776C→G polymorphism with Alzheimer’s type dementia: dependence on the 5, 10-methylenetetrahydrofolate reductase 1298A→C polymorphism genotype. Ann Clin Biochem 2014; 52:448-55. [DOI: 10.1177/0004563214561770] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2014] [Indexed: 01/08/2023]
Abstract
Background Decreased serum concentrations of vitamin B12 are associated with Alzheimer’s type dementia. The transcobalamin II gene (TCN2) 776C→G polymorphism affects transcobalamin II function as a carrier of vitamin B12 and might modify its availability. The association of the TCN2 776C→G polymorphism with Alzheimer’s type dementia is unclear and was investigated in the present study. Methods Case–control study including 27 individuals diagnosed with Alzheimer’s type dementia and 28 healthy controls. Serum concentrations of vitamin B12, homocysteine and other analytes were determined and the presence of TCN2 776C→G and 5, 10-methylenetetrahydrofolate reductase 1298A→C polymorphisms genotypes was ascertained by polymerase chain reaction–restriction fragment length polymorphism. Results Serum concentrations of vitamin B12 were lower while those of homocysteine were higher in patients than in controls ( P < 0.05). The frequency of individuals carrying at least one 5, 10-methylenetetrahydrofolate reductase 1298C allele was higher (59% versus 32%) while frequency of individuals harbouring at least one TCN2 776G allele was lower (58% versus 86%) in patients than in controls ( P < 0.05). Univariate logistic regression showed negative association of TCN2 776CG genotype with Alzheimer’s type dementia (OR = 0.17 versus CC genotype, P < 0.02). Multivariate logistic regression identified TCN2 776C→G polymorphism as independent predictor of Alzheimer’s type dementia together with higher concentrations of homocysteine, cholesterol and uric acid and lower concentrations of oestradiol. Association of TCN2 776C→G polymorphism with Alzheimer’s type dementia was observed for individuals carrying the 5,10-methylenetetrahydrofolate reductase 1298AA genotype but not the AC or CC genotypes, indicating interaction between the two polymorphisms. Conclusions The TCN2 776C→G polymorphism is negatively associated with Alzheimer’s type dementia, suggesting a protective role against the disease in subjects with the 5, 10-methylenetetrahydrofolate reductase 1298AA genotype.
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Affiliation(s)
- José F Cascalheira
- CICS-UBI – Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Mónica Gonçalves
- CICS-UBI – Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Madalena Barroso
- Research Institute for Medicines (iMed.UL), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal
| | - Rita Castro
- Research Institute for Medicines (iMed.UL), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal
| | | | - André Serpa
- CICS-UBI – Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Ana C Dias-Cabral
- CICS-UBI – Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Fernanda C Domingues
- CICS-UBI – Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
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Mitchell ES, Conus N, Kaput J. B vitamin polymorphisms and behavior: evidence of associations with neurodevelopment, depression, schizophrenia, bipolar disorder and cognitive decline. Neurosci Biobehav Rev 2014; 47:307-20. [PMID: 25173634 DOI: 10.1016/j.neubiorev.2014.08.006] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 07/11/2014] [Accepted: 08/18/2014] [Indexed: 11/16/2022]
Abstract
The B vitamins folic acid, vitamin B12 and B6 are essential for neuronal function, and severe deficiencies have been linked to increased risk of neurodevelopmental disorders, psychiatric disease and dementia. Polymorphisms of genes involved in B vitamin absorption, metabolism and function, such as methylene tetrahydrofolate reductase (MTHFR), cystathionine β synthase (CβS), transcobalamin 2 receptor (TCN2) and methionine synthase reductase (MTRR), have also been linked to increased incidence of psychiatric and cognitive disorders. However, the effects of these polymorphisms are often quite small and many studies failed to show any meaningful or consistent associations. This review discusses previous findings from clinical studies and highlights gaps in knowledge. Future studies assessing B vitamin-associated polymorphisms must take into account not just traditional demographics, but subjects' overall diet, relevant biomarkers of nutritional status and also analyze related genetic factors that may exacerbate behavioral effects or nutritional status.
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Affiliation(s)
- E Siobhan Mitchell
- Nestle Institute of Health Science, Innovation Park, EPFL Campus, Lausanne 1015, Switzerland.
| | - Nelly Conus
- Nestle Institute of Health Science, Innovation Park, EPFL Campus, Lausanne 1015, Switzerland
| | - Jim Kaput
- Nestle Institute of Health Science, Innovation Park, EPFL Campus, Lausanne 1015, Switzerland
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Kim HS, Lee BE, Jeon YJ, Rah H, Lee WS, Shin JE, Choi DH, Kim NK. Transcobalamin II (TCN267A>G andTCN2776C>G) and Transcobalamin II Receptor (TCblR1104C>T) Polymorphisms in Korean Patients with Idiopathic Recurrent Spontaneous Abortion. Am J Reprod Immunol 2014; 72:337-46. [DOI: 10.1111/aji.12256] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 03/18/2014] [Indexed: 11/28/2022] Open
Affiliation(s)
- Hyun Seok Kim
- Institute for Clinical Research; CHA Bundang Medical Center; CHA University; Seongnam South Korea
| | - Bo Eun Lee
- Institute for Clinical Research; CHA Bundang Medical Center; CHA University; Seongnam South Korea
- Department of Biomedical Science; College of Life Science; CHA University; Seongnam South Korea
| | - Young Joo Jeon
- Institute for Clinical Research; CHA Bundang Medical Center; CHA University; Seongnam South Korea
- Department of Biomedical Science; College of Life Science; CHA University; Seongnam South Korea
| | - HyungChul Rah
- Institute for Clinical Research; CHA Bundang Medical Center; CHA University; Seongnam South Korea
| | - Woo Sik Lee
- Fertility Center of CHA Gangnam Medical Center; CHA University; Seoul South Korea
| | - Ji Eun Shin
- Department of Obstetrics and Gynecology; CHA Bundang Medical Center; CHA University; Seongnam South Korea
| | - Dong Hee Choi
- Department of Obstetrics and Gynecology; CHA Bundang Medical Center; CHA University; Seongnam South Korea
| | - Nam Keun Kim
- Institute for Clinical Research; CHA Bundang Medical Center; CHA University; Seongnam South Korea
- Department of Biomedical Science; College of Life Science; CHA University; Seongnam South Korea
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19
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The effect of multiple single nucleotide polymorphisms in the folic acid pathway genes on homocysteine metabolism. BIOMED RESEARCH INTERNATIONAL 2014; 2014:560183. [PMID: 24524080 PMCID: PMC3913508 DOI: 10.1155/2014/560183] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 09/29/2013] [Accepted: 10/17/2013] [Indexed: 12/12/2022]
Abstract
Objective. To investigate the joint effects of the single nucleotide polymorphisms (SNPs) of genes in the folic acid pathway on homocysteine (Hcy) metabolism. Methods. Four hundred women with normal pregnancies were enrolled in this study. SNPs were identified by MassARRAY. Serum folic acid and Hcy concentration were measured. Analysis of variance (ANOVA) and support vector machine (SVM) regressions were used to analyze the joint effects of SNPs on the Hcy level. Results. SNPs of MTHFR (rs1801133 and rs3733965) were significantly associated with maternal serum Hcy level. In the different genotypes of MTHFR (rs1801133), SNPs of RFC1 (rs1051266), TCN2 (rs9606756), BHMT (rs3733890), and CBS (rs234713 and rs2851391) were linked with the Hcy level adjusted for folic acid concentration. The integrated SNPs scores were significantly associated with the residual Hcy concentration (RHC) (r = 0.247). The Hcy level was significantly higher in the group with high SNP scores than that in other groups with SNP scores of less than 0.2 (P = 0.000). Moreover, this difference was even more significant in moderate and high levels of folic acid. Conclusion. SNPs of genes in the folic acid pathway possibly affect the Hcy metabolism in the presence of moderate and high levels of folic acid.
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20
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Remacha AF, Sardà MP, Canals C, Queraltò JM, Zapico E, Remacha J, Carrascosa C. Role of serum holotranscobalamin (holoTC) in the diagnosis of patients with low serum cobalamin. Comparison with methylmalonic acid and homocysteine. Ann Hematol 2013; 93:565-9. [PMID: 24057896 DOI: 10.1007/s00277-013-1905-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 09/10/2013] [Indexed: 10/26/2022]
Abstract
Plasma holotranscobalamin (holoTC) transports active cobalamin. Decreased levels of holoTC have been considered to be the earliest marker of cobalamin (Cbl) deficiency. In this work, holoTC was evaluated in low or borderline serum Cbl (LB12) and a concordance analysis was carried out with methylmalonic acid (MMA) and homocysteine (Hcy). Levels of Cbl, holoTC, MMA, and Hcy were investigated in a reference group in 106 patients with LB12 (≤200 pmol/l) and in 27 with folate deficiency (FOL). HoloTC levels were evaluated by an automated immunoassay (Active B12, Abbott Lab, Abbott Park, IL, USA). Lower levels of holoTC were observed in both LB12 and FOL groups (reference group vs LB12; p < 0.0001. Reference group vs FOL; p = 0.002). HoloTC levels were lower in LB12 than in FOL (p = 0.001). In LB12, concordance between Hcy and MMA was 82.1 % (chi-square test, p < 0.001; Kappa Index, 0.64, p < 0.0001). Concordance between Hcy and holoTC was 62 % (chi-square test, p = 0.006; Kappa index, 0.245, p = 0.006). Concordance between holoTC and MMA was 55.6 % (p = 0.233). Some cases with LB12 and elevated MMA did not show decreased holoTC. By contrast, MMA and Hcy were not increased in some patients with low holoTC and LB12. In conclusion, levels of holoTC were decreased in LB12 and FOL. In LB12 patients, holoTC concordance with MMA was poor. MMA/Hcy levels were not increased in a significant number of subjects with LB12 and low holoTC. This profile was found in iron deficiency. The significance of these changes remains to be clarified.
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Affiliation(s)
- A F Remacha
- Hematology Department, Hospital de Sant Pau, Avda Padre Claret 167, Barcelona, 08025, Spain,
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21
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Quadros EV, Sequeira JM. Cellular uptake of cobalamin: transcobalamin and the TCblR/CD320 receptor. Biochimie 2013; 95:1008-18. [PMID: 23415653 PMCID: PMC3902480 DOI: 10.1016/j.biochi.2013.02.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 02/01/2013] [Indexed: 02/06/2023]
Abstract
Cellular uptake of cobalamin is facilitated by a receptor-mediated endocytosis process involving transcobalamin, a plasma protein that binds cobalamin and a cell surface receptor that specifically binds transcobalamin saturated with cobalamin. Intracellular Cbl concentration is maintained by modulating the expression of the receptor, which is cell cycle associated with highest expression in actively proliferating cells and an efflux system that shunts the excess cobalamin out of the cells for mobilization to other tissues where it is most needed. This review describes the process, proteins involved and genes encoding these proteins.
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Affiliation(s)
- Edward V Quadros
- Departments of Medicine / Cell Biology, SUNY- Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
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Carmel R. Diagnosis and management of clinical and subclinical cobalamin deficiencies: why controversies persist in the age of sensitive metabolic testing. Biochimie 2013; 95:1047-55. [PMID: 23416723 DOI: 10.1016/j.biochi.2013.02.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Accepted: 02/08/2013] [Indexed: 01/11/2023]
Abstract
In the past two decades, sensitive biochemical tests have uncovered cobalamin deficiency much more frequently than ever before. Almost all cases involve mild, biochemical changes without clinical manifestations (subclinical cobalamin deficiency; SCCD), whose health impact is unclear. Because the causes of SCCD are most often unknown, nonmalabsorptive, and seldom documented, controversy and confusion surround the diagnostic criteria and, inevitably, consequences and management of SCCD. To complicate matters, our grasp of the rarer clinical deficiency, usually a serious, progressive medical disease rooted in severe malabsorption, has receded as absorption testing has disappeared. Reexamining the accumulation of assumptions and misperceptions about cobalamin deficiency and distinguishing SCCD from clinical deficiency is long overdue. The biology of cobalamin provides an important starting point: cobalamin stores exceed daily losses so greatly and binding proteins regulate absorption so effectively that deficiency typically achieves clinical expression only after years of severe, relentless malabsorption. Dietary insufficiency, mild, partial malabsorption, and other incomplete, intermittent causes can usually produce only SCCD. Thus, the most fundamental difference between the two deficiencies is the relentlessness of the underlying cause, which determines prognosis and health impact. Inattention to absorptive status has exacerbated the limitations of biochemical testing. All the biochemical tests are highly sensitive but specificity is poor, no diagnostic gold standard exists, and diagnostic cutpoints fluctuate excessively. To limit the adverse diagnostic consequences, the diagnosis of SCCD, whose need for treatment is unclear, should be deferred unless at least two tests are abnormal. Indeed, cobalamin biology indicates that the absorption system, while enhancing cobalamin delivery, also sets a strict upper limit on it, which suggests that cobalamin excess is undesirable. Solving cobalamin deficiency requires balanced assessment of the different imperatives of clinical and public health concerns, better rationalization of diagnostic testing, consistent definitions of normality in relation to SCCD, and rational cutpoint selection.
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Affiliation(s)
- Ralph Carmel
- Department of Medicine, New York Methodist Hospital, Brooklyn, NY, USA.
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23
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Vitamin B-12 status during pregnancy and child's IQ at age 8: a Mendelian randomization study in the Avon longitudinal study of parents and children. PLoS One 2012; 7:e51084. [PMID: 23227234 PMCID: PMC3515553 DOI: 10.1371/journal.pone.0051084] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 11/01/2012] [Indexed: 11/19/2022] Open
Abstract
Vitamin B-12 is essential for the development and maintenance of a healthy nervous system. Brain development occurs primarily in utero and early infancy, but the role of maternal vitamin B-12 status during pregnancy on offspring cognitive function is unclear. In this study we assessed the effect of vitamin B-12 status in well-nourished pregnant women on the cognitive ability of their offspring in a UK birth cohort (ALSPAC). We then examined the association of SNPs in maternal genes FUT2 (rs492602) and TCN2 (rs1801198, rs9606756) that are related to plasma vitamin B-12, with offspring IQ. Observationally, there was a positive association between maternal vitamin B-12 intake and child’s IQ that was markedly attenuated after adjustment for potential confounders (mean difference in offspring IQ score per doubling of maternal B-12 intake, before adjustment: 2.0 (95% CI 1.3, 2.8); after adjustment: 0.7 (95% CI −0.04, 1.4)). Maternal FUT2 was weakly associated with offspring IQ: mean difference in IQ per allele was 0.9 (95% CI 0.1, 1.6). The expected effect of maternal vitamin B-12 on offspring IQ, given the relationships between SNPs and vitamin B-12, and SNPs and IQ was consistent with the observational result. Our findings suggest that maternal vitamin B-12 may not have an important effect on offspring cognitive ability. However, further examination of this issue is warranted.
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Biselli JM, Zampieri BL, Goloni-Bertollo EM, Haddad R, Fonseca MFR, Eberlin MN, Vannucchi H, Carvalho VM, Pavarino EC. Genetic polymorphisms modulate the folate metabolism of Brazilian individuals with Down syndrome. Mol Biol Rep 2012; 39:9277-84. [PMID: 22903356 DOI: 10.1007/s11033-012-1629-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 04/16/2012] [Indexed: 12/01/2022]
Abstract
Individuals with Down syndrome (DS) carry three copies of the Cystathionine β-synthase (CβS) gene. The increase in the dosage of this gene results in an altered profile of metabolites involved in the folate pathway, including reduced homocysteine (Hcy), methionine, S-adenosylhomocysteine (SAH) and S-adenosylmethionine (SAM). Furthermore, previous studies in individuals with DS have shown that genetic variants in genes involved in the folate pathway influence the concentrations of this metabolism's products. The purpose of this study is to investigate whether polymorphisms in genes involved in folate metabolism affect the plasma concentrations of Hcy and methylmalonic acid (MMA) along with the concentration of serum folate in individuals with DS. Twelve genetic polymorphisms were investigated in 90 individuals with DS (median age 1.29 years, range 0.07-30.35 years; 49 male and 41 female). Genotyping for the polymorphisms was performed either by polymerase chain reaction (PCR) based techniques or by direct sequencing. Plasma concentrations of Hcy and MMA were measured by liquid chromatography-tandem mass spectrometry as previously described, and serum folate was quantified using a competitive immunoassay. Our results indicate that the MTHFR C677T, MTR A2756G, TC2 C776G and BHMT G742A polymorphisms along with MMA concentration are predictors of Hcy concentration. They also show that age and Hcy concentration are predictors of MMA concentration. These findings could help to understand how genetic variation impacts folate metabolism and what metabolic consequences these variants have in individuals with trisomy 21.
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Affiliation(s)
- J M Biselli
- Departamento de Biologia Molecular, Faculdade de Medicina de São José do Rio Preto (FAMERP), Unidade de Pesquisa em Genética e Biologia Molecular (UPGEM), Av. Brigadeiro Faria Lima, n.o 5416-Bloco U-6, São José do Rio Preto, SP, CEP: 15.090-000, Brazil
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Abstract
PURPOSE OF REVIEW This review focuses on recent developments and controversies in the diagnosis, consequences, and management of subclinical cobalamin deficiency (SCCD), which affects many elderly persons. RECENT FINDINGS Diagnosis of SCCD depends exclusively on biochemical tests whose individual limitations suggest that combinations of tests are needed, especially in epidemiologic research. The causes of SCCD are unknown in more than 60% of cases, which limits prognostic predictions and identification of health consequences. After years of varying, often inconclusive associations, new clinical trials suggest that homocysteine reduction by high doses of folic acid, cobalamin, and pyridoxine may reduce progression of structural brain changes and cognitive impairment, especially in predisposed individuals. The causative or contributory roles, if any, of SCCD itself in cognitive dysfunction require direct study. If the findings are confirmed, high-dose supplementation with three vitamins will probably be more effective than fortification of the diet. SUMMARY The story of SCCD, which is severalfold times more common in the elderly than clinical cobalamin deficiency but also differs from it in arising only infrequently from severe malabsorption and thus being less likely to progress, continues to evolve. Preventive benefits need to be confirmed and expanded, and will require fuller understanding of SCCD pathophysiology, natural history, and health consequences.
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