Bioinformatics and wet laboratory analysis of rs1800562 to predict genetic aetiology of iron overload in Nigeria

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S145-S146
Author(s):  
A B Bolarinwa ◽  
F Onawoga
Keyword(s):  
Iron Overload ◽  
In Silico ◽  
Protein Localization ◽  
Restriction Enzymes ◽  
Protein Product ◽  
Laboratory Analysis ◽  
Hfe Gene ◽  
Excess Iron ◽  
Stability Change ◽  
Suitable Restriction

Abstract Introduction/Objective The most reported single nucleotide polymorphism (SNP) of the HFE gene is rs1800562, representing the substitution of Adenine for Guanine at position 847 of the HFE gene. This has been widely implicated in hereditary haemochromatosis and other conditions like altered cholesterol balance, Alzheimer’s disease and cutaneous photosensitivity. Abnormal HFE protein resulting from the mutant HFE gene leads to formation of excess iron which has been postulated as likely mechanism for these diseases. Although there is evidence of iron overload in Africans, only few studies have explored possible genetic causes, and prevalence of rs1800562 is not known in West African population. Hence the need to determine the prevalence of rs1800562 in Nigeria using computational and wet laboratory approach. Methods/Case Report Details of rs1800562 were retrieved from Ensembl Genome Browser version 99. Severity of the consequences of this SNP on protein product was determined using bioinformatics tools including SIFT, Polyphen, Mutation Assessor, HOPE, I-mutant and MutPred2. Genotyping of rs1800562 was done In silico using restriction fragment length polymorphism (RFLP). Primer3plus was used for primer design, NCBI BLAST and SMS were used for primer validation. We used Webcutter 2.0 to determine suitable restriction enzymes. The genotyping was simulated using USCS virtual PCR and RestrictionMapper. Whole blood samples were obtained from 200 participants selected randomly from a pool of blood donors. DNA was extracted and flanking region of rs1800562 was amplified. The amplified product was digested by RSA1and fragments examined on agarose gel electrophoresis. Results (if a Case Study enter NA) The MAF was found to be 0.01 globally and 0.02 in Africa. In the two Nigerian population examined (Yoruba and Esan population), MAF was 0.00. Mutation Assessor and SIFT Polyphen consistently predicted the mutation to be of severe consequences. Analysis on HOPE, I-mutant and Mutpred2 revealed loss of protein stability, change in net charges affecting the HFE protein localization and its interaction with other proteins. All the participants in the wet laboratory analysis were homozygous for the wild type allele of rs1800562 (MAF=0). Conclusion This study confirmed the In silico prediction of the absence of rs1800562 in Nigeria. Future studies should focus on other SNPs of the HFE gene as well as other gene involved in iron metabolism.

scholarly journals Secondary Hemochromatosis due to Chronic Oral Iron Supplementation

2017 ◽  
Vol 2017 ◽  
pp. 1-3
Author(s):  
Ronald Lands ◽  
Emmanuel Isang
Keyword(s):  
Diabetes Mellitus ◽  
Iron Overload ◽  
Liver Damage ◽  
Ferrous Sulfate ◽  
Iron Supplementation ◽  
Geriatric Patients ◽  
Hepatic Cirrhosis ◽  
Hfe Gene ◽  
Excess Iron ◽  
Chronic Ingestion

Iron may accumulate in excess due to a mutation in the HFE gene that upregulates absorption or when it is ingested or infused at levels that exceed the body’s ability to clear it. Excess iron deposition in parenchymal tissue causes injury and ultimately organ dysfunction. Diabetes mellitus and hepatic cirrhosis due to pancreas and liver damage are just two examples of diseases that result from iron overload. Despite the rapid growth of information regarding iron metabolism and iron overload states, the most effective treatment is still serial phlebotomies. We present a patient who developed iron overload due to chronic ingestion of oral ferrous sulfate. This case illustrates the importance of querying geriatric patients regarding their use of nonprescription iron products without a medical indication.

Dysmetabolic iron overload syndrome and its relationship with HFE gene mutations and with liver steatosis

2020 ◽  
Vol 52 (6) ◽  
pp. 683-685
Author(s):  
Agustín Castiella ◽  
Iratxe Urreta ◽  
Eva Zapata ◽  
MªDolores de Juan ◽  
José Mª Alústiza ◽  
...  
Keyword(s):  
Iron Overload ◽  
Liver Steatosis ◽  
Gene Mutations ◽  
Hfe Gene ◽  
Hfe Gene Mutations

Novel mutation in ferroportin1 is associated with autosomal dominant hemochromatosis

Blood ◽  
2002 ◽  
Vol 100 (2) ◽  
pp. 692-694 ◽  
Author(s):  
Daniel F. Wallace ◽  
Palle Pedersen ◽  
Jeannette L. Dixon ◽  
Peter Stephenson ◽  
Jeffrey W. Searle ◽  
...  
Keyword(s):  
Iron Transport ◽  
Autosomal Recessive ◽  
Iron Homeostasis ◽  
Autosomal Dominant ◽  
Novel Mutation ◽  
Hfe Gene ◽  
Excess Iron ◽  
Chromosome 1Q ◽  
Australian Family ◽  
Autosomal Recessive Pattern

Abstract Hemochromatosis is a common disorder characterized by excess iron absorption and accumulation of iron in tissues. Usually hemochromatosis is inherited in an autosomal recessive pattern and is caused by mutations in the HFE gene. Less common non-HFE–related forms of hemochromatosis have been reported and are caused by mutations in the transferrin receptor 2 gene and in a gene localized to chromosome 1q. Autosomal dominant forms of hemochromatosis have also been described. Recently, 2 mutations in theferroportin1 gene, which encodes the iron transport protein ferroportin1, have been implicated in families with autosomal dominant hemochromatosis from the Netherlands and Italy. We report the finding of a novel mutation (V162del) in ferroportin1 in an Australian family with autosomal dominant hemochromatosis. We propose that this mutation disrupts the function of the ferroportin1 protein, leading to impaired iron homeostasis and iron overload.

scholarly journals Iron age: novel targets for iron overload

Hematology ◽  
2014 ◽  
Vol 2014 (1) ◽  
pp. 216-221 ◽  
Author(s):  
Carla Casu ◽  
Stefano Rivella
Keyword(s):  
Iron Overload ◽  
Iron Age ◽  
Iron Metabolism ◽  
Iron Absorption ◽  
Hereditary Hemochromatosis ◽  
Therapeutic Approaches ◽  
Hepcidin Expression ◽  
Beneficial Effects ◽  
Excess Iron ◽  
Major Factors

Abstract Excess iron deposition in vital organs is the main cause of morbidity and mortality in patients affected by β-thalassemia and hereditary hemochromatosis. In both disorders, inappropriately low levels of the liver hormone hepcidin are responsible for the increased iron absorption, leading to toxic iron accumulation in many organs. Several studies have shown that targeting iron absorption could be beneficial in reducing or preventing iron overload in these 2 disorders, with promising preclinical data. New approaches target Tmprss6, the main suppressor of hepcidin expression, or use minihepcidins, small peptide hepcidin agonists. Additional strategies in β-thalassemia are showing beneficial effects in ameliorating ineffective erythropoiesis and anemia. Due to the suppressive nature of the erythropoiesis on hepcidin expression, these approaches are also showing beneficial effects on iron metabolism. The goal of this review is to discuss the major factors controlling iron metabolism and erythropoiesis and to discuss potential novel therapeutic approaches to reduce or prevent iron overload in these 2 disorders and ameliorate anemia in β-thalassemia.

Hereditary Hemochromatosis Since Discovery of the HFE Gene

2001 ◽  
Vol 47 (7) ◽  
pp. 1147-1156 ◽  
Author(s):  
Elaine Lyon ◽  
Elizabeth L Frank
Keyword(s):  
Molecular Genetic ◽  
Hereditary Hemochromatosis ◽  
Phenotypic Expression ◽  
Protein Product ◽  
Population Screening ◽  
The Body ◽  
Hfe Gene ◽  
Molecular Testing ◽  
Disease Mechanism ◽  
Biochemical Tests

Abstract Background: Hereditary hemochromatosis is an inherited disorder of iron metabolism that is characterized by excessive iron deposition in major organs of the body. Chronic increased iron absorption leads to multiorgan dysfunction. Since the discovery of the gene responsible for the majority of cases, research has progressed rapidly to identify the gene product, the effects of mutations, and the implications for different populations. The protein product of the HFE gene is a transmembrane glycoprotein, termed HFE, that modulates iron uptake. Mutations in the HFE protein compromise its function and produce disease symptoms. Two mutations, C282Y and H63D, have been linked to the majority of disease cases. Approach: We reviewed the recent literature for the molecular basis of hereditary hemochromatosis. Genotypic information was combined with biochemical and clinical phenotypic information to achieve a better understanding of the disease mechanism. Content: This review provides a comprehensive discussion of known mutations in the HFE gene and their phenotypic expression. Diagnostic criteria using molecular genetic techniques in conjunction with traditional biochemical tests are provided. Current methods and limitations of molecular testing are examined in detail. A strategy for population screening and an algorithm for diagnosis that incorporates molecular testing are presented. Treatment by therapeutic phlebotomy and the use of blood obtained from hemochromatosis patients are discussed. Summary: Although the disease mechanism has not been completely elucidated, phenotypic and penetrance data are becoming available. Controversy still exists concerning the role of genetic testing in diagnosis and population screening.

Lack of association of primary iron overload and common HFE gene mutations with liver cirrhosis in adult Indian population

2011 ◽  
Vol 30 (4) ◽  
pp. 161-165 ◽  
Author(s):  
Shalu Jain ◽  
Sarita Agarwal ◽  
Parag Tamhankar ◽  
Prashant Verma ◽  
Gourdas Choudhuri
Keyword(s):  
Liver Cirrhosis ◽  
Iron Overload ◽  
Indian Population ◽  
Gene Mutations ◽  
Hfe Gene ◽  
Hfe Gene Mutations

Iron Overload Strongly Correlates with Acute Graft-Versus-Host-Disease of the Liver and Treatment Related Mortality after Allogeneic Hematopoetic Cell Transplantation (HCT).

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1812-1812
Author(s):  
Ann-Kathrin Eisfeld ◽  
Ralph Burkhardt ◽  
Daniel Teupser ◽  
Sabine Schroeder ◽  
Rainer Krahl ◽  
...  
Keyword(s):  
Risk Factors ◽  
Iron Overload ◽  
Retrospective Analysis ◽  
Acute Gvhd ◽  
Chronic Gvhd ◽  
Hfe Gene ◽  
Strongly Correlated ◽  
Body Iron ◽  
Treatment Related Mortality ◽  
Related Mortality

Abstract Risk factors for morbidity and treatment related mortality (TRM) following HCT have been well defined in retrospective analysis and prospective validations. These include disease-, recipient- and donor-specific characteristics, but not treatment related factors. Considering that patients undergoing HCT usually receive multiple blood transfusions (BT) and that mutations of the HFE gene are common in the European population, we asked the question if iron overload and HFE mutations were risk factors for complications following HCT. Patients and methods: From January 2001 to December 2004, 265 consecutive patients (142 m/123 f; median age 47 y) received HCT at the University of Leipzig. Patients suffered from acute leukaemia (n=113; 43%), chronic leukaemia (n=75; 28%), lymphoma (n=37; 14%), multiple myeloma (n=21; 8%), and others (n=19; 7%). Preparative regimen consisted of Cyclophosphamid 120 mg/kg and 12 Gy TBI in 145 (55%) patients. The remaining 120 (45%) patients were conditioned with Fludarabin 30 mg/m2/day for 3 days and 2 Gy TBI. HCT was performed from matched related donors in 85 (32%) and matched unrelated donors (MUD) in 180 (68%) patients. Patients and donors were screened for mutant HFE genes by PCR using LightCycler, Roche. Serum ferritin (reference values 30–400 ng/ml) was measured at a median of 1 month after HCT. At the time of measurement, patients had to be in good clinical condition with normal C-reactive protein. Results: Elevated iron stores were present in 86% of patients (median ferritin 1697 ng/ml). At a median of 25 (range 7–55) months after HCT, 92 (35%) patients have died from relapse (n= 27; 29%) or TRM (n= 65; 71%). TRM occurred at a median of 4 months after HCT. Median ferritin in patients who died (measured at a median of 3 months prior to death) and in surviving patients were 3815 and 1146 ng/ml respectively (p<0.0001). The median number of BT at HCT in the 2 groups were 34, and 16 unit respectively (p<0.0001). MUD, CMV-serological status and the gender of the donor did not correlate with TRM. In multivariate analysis, ferritin and BT strongly correlated with TRM (p<0.0001). Mutant HFE genes were found in 98 (37%) patients prior to HCT [heterozygous (het; n=82, 84%), compound (n=9; 9%), homozygous (homo; n=7; 7%). Similarly, 99 (37%) donors showed mutant HFE genes [het, n=86 (87%), compound, n=8 (8%), and homo, n=5 (5%)]. After HCT, all patients expressed donor HFE genotype. HFE genotype of patients and donors did not correlate with TRM. Acute GvHD > grade II was significantly more in pts who died (p=0.0002). Acute GvHD of the liver strongly correlated with excess body iron (p=0.009). Interestingly, chronic GvHD of the skin and liver tended to be more frequent in patients with mutant HFE genes prior to HCT (p=0.03). Conclusions: This is, to our knowledge, the first retrospective analysis where excess body iron and the number of BT at HCT strongly correlated with acute GvHD of the liver and TRM after HCT. These data must be confirmed in prospective studies. Whether morbidity and TRM after HCT can be reduced by iron chelation needs to be evaluated.

Phlebotomy as an Effective Treatment for Iron Overload after Allogeneic Hematopoietic Cell Transplantation: Iron Depletion Kinetics Are Influenced by the Donor Hemochromatosis (HFE) Genotype.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3717-3717
Author(s):  
Ann-Kathrin Eisfeld ◽  
Medical Student ◽  
Ralph Burkhardt ◽  
Sabine Schroeder ◽  
Rainer Krahl ◽  
...  
Keyword(s):  
Liver Function ◽  
Iron Overload ◽  
Cell Transplantation ◽  
Serum Ferritin ◽  
Hematopoietic Cell Transplantation ◽  
Hematopoietic Cell ◽  
Hfe Gene ◽  
Blood Transfusions ◽  
Iron Depletion ◽  
Iron Stores

Abstract Introduction: Iron metabolism plays an important role in hematopoiesis and immune response. In the present project, body iron stores and factors affecting iron storage such as HFE genotype and the number of blood transfusions were evaluated in patients after allogeneic hematopoietic cell transplantation (HCT). In patients with iron overload, the effect of phlebotomy (PT) on iron stores was analysed in correlation to HFE mutations. Patients and methods: Serum ferritin was measured in 201 consecutive patients transplanted from January 2001 to December 2004 at the University of Leipzig. After excluding patients with normal body iron (serum ferritin levels between 30–400 ng/ml) and patients surviving less than 4 months after HCT, 61 patients (31 males/30 females; median age 48 y) treated with PT were evaluated. Diagnoses included acute leukemias (n=29; 48%), chronic leukemias (n=15; 24%), MDS (n=8; 13%) and others (n=9; 15%). 33 patients (54%) were conditioned with Cyclophosphamid 120 mg/kg and 12 Gy TBI. Patients with unrelated donors received ATG 15 mg/kg/day for 3 days. The remaining patients (n=28; 46%) were treated with Fludarabin 30 mg/m2/day for 3 days and TBI 2 Gy applied once. Donors were matched related in 21 (34%) and matched unrelated in 40 (66%) patients. HFE genotype of patients and donors were analysed by real time PCR using a LightCycler, Roche. The effectiveness of PT was assessed by serum ferritin and liver function test evaluation. Results: The majority of patients after HCT (n=172; 86%) had iron overload with a median ferritin of 1697 ng/ml. From these, 61 patients received PT. These patients received a median of 28 (range 2–102) units of blood transfusions. Acute GvHD ≥ grade II was present in 25 (41%) and chronic GvHD in 19 (31%) patients. Elevated SGPT/SGOT and AP were detected in 34 (56%) and 39 (64%) patients respectively. Mutations in the HFE gene were found in 14 (25%) prior to HCT: heterozygosity (het) for H63D (n=10), for C282Y (n=3) and homozygosity for H63D (n=1). Similarly, 22 donors (40%) showed het. for H63D (n=12), for C282Y (n=4) and for S65C (n=4). Two donors were homozygous for S65C. After HCT, all pts expressed donor HFE genotype. PT was performed every 2 weeks with a median of 200 ml blood removed in one session. Interestingly, median Hemoglobin (Hb) rose under PT (p<0.0001). PT resulted in a significant depletion of iron stores (p<0.0001), improvement in SGPT/SGOT (p=0.002), bilirubin (p<0.0001), and AP (p=0.01). In multivariate analysis, a slower rate of iron depletion significantly correlated with mutated donor HFE genotype (p=0.002). In such patients less iron/ml blood were removed per PT and more often PT were required compared to patients with wildtype HFE donors. Conclusions: Iron overload is a frequent complication after HCT. PT is highly effective in removing excess iron and improving Hb and liver function associated with iron overload after HCT. Patients transplanted from a donor with a mutant HFE gene showed slower iron depletion kinetics by PT compared to patients transplanted from donors with wildtype HFE. The role of donor HFE genotype is currently being analysed in patients after HCT.

Iron Overload in C282Y Heterozygotes: Identification of New Rare HFE Gene Mutants and a Step Strategy for Diagnosis.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1859-1859
Author(s):  
Patricia Aguilar-Martinez ◽  
Severine Cunat ◽  
Fabienne Becker ◽  
Francois Blanc ◽  
Marlene Nourrit ◽  
...  
Keyword(s):  
Iron Overload ◽  
Iron Status ◽  
Hereditary Hemochromatosis ◽  
Genetic Defect ◽  
Transferrin Saturation ◽  
Hfe Gene ◽  
Compound Heterozygous ◽  
Exon 2 ◽  
High Iron ◽  
Iron Parameters

Abstract Introduction: Homozygozity for the p.Cys282Tyr (C282Y) mutation of the HFE gene is the main genotype associated with the common form of adult hereditary hemochromatosis. C282Y carriers do not usually develop iron overload, unless they have additional risk factors such as liver diseases, a dysmetabolic syndrome or an associated genetic defect. The commonest is the compound heterozygous state for C282Y and the widespread p.His63Asp (H63D) variant allele. However, a few rare HFE mutations can be found on the 6th chromosome in trans, some of which are of clinical interest to fully understand the disorder. Patients and Methods: We recently investigated four C282Y carrier patients with unusually high iron parameters, including increased levels of serum ferritin (SF), high transferrin saturation (TS) and high iron liver content measured by MRI. They were males, aged 37, 40, 42, 47 at diagnosis. Two brothers (aged 40 and 42) were referred separately. The HFE genotype, including the determination of the C282Y, H63D and S65C mutations was performed using PCR-RFLP. HFE sequencing was undertaken using the previously described SCA method (1). Sequencing of other genes (namely, HAMP, HJV/HFE2, SLC40A1, TFR2) was possibly performed in a last step using the same method. Results: We identified three rare HFE mutant alleles, two of which are undescribed, in the four studied patients. One patient bore a 13 nucleotide-deletion in exon 6 (c.[1022_1034del13], p.His341_Ala345>LeufsX119), which is predicted to lead to an abnormal, elongated protein. The two brothers had a substitution of the last nucleotide of exon 2 (c.[340G>A], p.Glu114Lys) that may modify the splicing of the 2d intron. The third patient, who bore an insertion of a A in exon 4 (c.[794dupA],p.[trp267LeufsX80]), has already been reported (1). Discussion: A vast majority of C282Y carriers will not develop iron overload and can be reassured. However, a careful step by step strategy at the clinical and genetic levels may allow to correctly identify those patients deserving further investigation. First, clinical examination and the assessment of iron parameters (SF and TS) allow identifying C282Y heterozygotes with an abnormal iron status. Once extrinsic factors such as heavy alcohol intake, virus or a dysmetabolic syndrome have been excluded, MRI is very useful to authenticate a high liver iron content. Second, HFE genotype must first exclude the presence of the H63D mutation. Compound heterozygozity for C282Y and H63D, a very widespread condition in our area, is usually associated with mild iron overload. Third, HFE sequencing can be undertaken and may identify new HFE variants as described here. The two novel mutations, a frameshift modifying the composition and the length of the C terminal end of the HFE protein and a substitution located at the last base of an exon, are likely to lead to an impaired function of HFE in association with the C282Y mutant. However, it is noteworthy that three of the four patients were diagnosed relatively late, after the 4th decade, as it is the case for C282Y homozygotes. Three further unrelated patients are currently under investigation in our laboratory for a similar clinical presentation. Finally, it can be noted that in those patients who will not have a HFE gene mutant identified, analysis of other genes implicated in iron overload must be performed to search for digenism or multigenism. None of our investigated patients had an additional gene abnormality.

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