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Wiedemann A, Oussalah A, Lamireau N, Théron M, Julien M, Mergnac JP, Augay B, Deniaud P, Alix T, Frayssinoux M, Feillet F, Guéant JL. Clinical, phenotypic and genetic landscape of case reports with genetically proven inherited disorders of vitamin B 12 metabolism: A meta-analysis. Cell Rep Med 2022; 3:100670. [PMID: 35764087 PMCID: PMC9381384 DOI: 10.1016/j.xcrm.2022.100670] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 11/22/2021] [Accepted: 06/02/2022] [Indexed: 10/31/2022]
Abstract
Inherited disorders of B12 metabolism produce a broad spectrum of manifestations, with limited knowledge of the influence of age and the function of related genes. We report a meta-analysis on 824 patients with a genetically proven diagnosis of an inherited disorder of vitamin B12 metabolism. Gene clusters and age categories are associated with patients' manifestations. The "cytoplasmic transport" cluster is associated with neurological and ophthalmological manifestations, the "mitochondrion" cluster with hypotonia, acute metabolic decompensation, and death, and the "B12 availability" and "remethylation" clusters with anemia and cytopenia. Hypotonia, EEG abnormalities, nystagmus, and strabismus are predominant in the younger patients, while neurological manifestations, such as walking difficulties, peripheral neuropathy, pyramidal syndrome, cerebral atrophy, psychiatric disorders, and thromboembolic manifestations, are predominant in the older patients. These results should prompt systematic checking of markers of vitamin B12 status, including homocysteine and methylmalonic acid, when usual causes of these manifestations are discarded in adult patients.
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Affiliation(s)
- Arnaud Wiedemann
- Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, INSERM UMR_S 1256, 54000 Nancy, France; Department of Pediatrics, University Hospital of Nancy, 54000 Nancy, France; Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000 Nancy, France
| | - Abderrahim Oussalah
- Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, INSERM UMR_S 1256, 54000 Nancy, France; Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000 Nancy, France; Department of Molecular Medicine, Division of Biochemistry, Molecular Biology, Nutrition, and Metabolism, University Hospital of Nancy, 54000 Nancy, France
| | - Nathalie Lamireau
- Department of Pediatrics, University Hospital of Nancy, 54000 Nancy, France
| | - Maurane Théron
- Department of Pediatrics, University Hospital of Nancy, 54000 Nancy, France
| | - Melissa Julien
- Department of Molecular Medicine, Division of Biochemistry, Molecular Biology, Nutrition, and Metabolism, University Hospital of Nancy, 54000 Nancy, France
| | | | - Baptiste Augay
- Department of Pediatrics, University Hospital of Nancy, 54000 Nancy, France
| | - Pauline Deniaud
- Department of Pediatrics, University Hospital of Nancy, 54000 Nancy, France
| | - Tom Alix
- Department of Molecular Medicine, Division of Biochemistry, Molecular Biology, Nutrition, and Metabolism, University Hospital of Nancy, 54000 Nancy, France
| | - Marine Frayssinoux
- Department of Molecular Medicine, Division of Biochemistry, Molecular Biology, Nutrition, and Metabolism, University Hospital of Nancy, 54000 Nancy, France
| | - François Feillet
- Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, INSERM UMR_S 1256, 54000 Nancy, France; Department of Pediatrics, University Hospital of Nancy, 54000 Nancy, France; Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000 Nancy, France
| | - Jean-Louis Guéant
- Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, INSERM UMR_S 1256, 54000 Nancy, France; Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000 Nancy, France; Department of Molecular Medicine, Division of Biochemistry, Molecular Biology, Nutrition, and Metabolism, University Hospital of Nancy, 54000 Nancy, France.
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Abstract
Objective: Transcobalamin II deficiency is a rare autosomal recessive disease characterized by decreased cobalamin availability, which in turn causes accumulation of homocysteine and methylmalonic acid. The presenting clinical features are failure to thrive, diarrhea, megaloblastic anemia, pancytopenia, neurologic abnormalities, and also recurrent infections due to immune abnormalities in early infancy. Materials and Methods: Here, we report the clinical and laboratory features of six children with transcobalamin II deficiency who were all molecularly confirmed. Results: The patients were admitted between 1 and 7 months of age with anemia or pancytopenia. Unexpectedly, one patient had a serum vitamin B12 level lower than the normal range and another one had nonsignificantly elevated serum homocysteine levels. Four patients had lymphopenia, four had neutropenia and three also had hypogammaglobulinemia. Suggesting the consideration of transcobalamin II deficiency in the differential diagnosis of immune deficiency. Hemophagocytic lymphohistiocytosis was also detected in one patient. Furthermore, two patients had vacuolization in the myeloid lineage in bone marrow aspiration, which may be an additional finding of transcobalamin II deficiency. The hematological abnormalities in all patients resolved after parenteral cobalamin treatment. In follow-up, two patients showed neurological impairments such as impaired speech and walking. Among our six patients who were all molecularly confirmed, two had the mutation that was reported in transcobalamin II-deficient patients of Turkish ancestry. Also, a novel TCN2 gene mutation was detected in one of the remaining patients. Conclusion: Transcobalamin II deficiency should be considered in the differential diagnosis of infants with immunological abnormalities as well as cytopenia and neurological dysfunction. Early recognition of this rare condition and initiation of adequate treatment is critical for control of the disease and better prognosis.
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Affiliation(s)
- Selma Ünal
- Mersin University Faculty of Medicine, Department of Pediatric Hematology, Mersin, Turkey
| | - Feryal Karahan
- Mersin University Faculty of Medicine, Department of Pediatric Hematology, Mersin, Turkey
| | - Tuğba Arıkoğlu
- Mersin University Faculty of Medicine, Department of Pediatric Allergy and Immunology, Mersin, Turkey
| | - Asuman Akar
- Mersin University Faculty of Medicine, Department of Pediatric Infectious Diseases, Mersin, Turkey
| | - Semanur Kuyucu
- Mersin University Faculty of Medicine, Department of Pediatric Allergy and Immunology, Mersin, Turkey
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Arora K, Sequeira JM, Quadros EV. Maternofetal transport of vitamin B 12: role of TCblR/ CD320 and megalin. FASEB J 2017; 31:3098-3106. [PMID: 28351841 DOI: 10.1096/fj.201700025r] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/13/2017] [Indexed: 11/11/2022]
Abstract
Vitamin B12 deficiency causes megaloblastic anemia and neurologic disorder in humans. Gene defects of transcobalamin (TC) and the transcobalamin receptor (TCblR), needed for cellular uptake of the TC-bound B12, do not confer embryonic lethality. TC deficiency can produce the hematologic and neurologic complications after birth, whereas TCblR/CD320 gene defects appear to produce mild metabolic changes. Alternate maternofetal transport mechanisms appear to provide adequate B12 to the fetus. To understand this mechanism, we evaluated the role of TC, TCblR/CD320, and megalin in maternofetal transport of B12 in a TCblR/CD320-knockout (KO) mouse. Our results showed high expression of TCblR/CD320 in the labyrinth of the placenta, embryonic brain, and spinal column in wild-type (WT) mice. Megalin expression was about the same in both WT and KO mouse visceral yolk sac, brain, and spinal column. Megalin mRNA was down-regulated in the KO embryonic spinal cord (SC) and kidneys. Megalin expression remained unaltered in adult WT and KO mouse brain, SC, and kidneys. Injected dsRed-TC-B12 and TC-57CoB12 accumulated in the visceral yolk sac of KO mice where megalin is expressed and provides an alternate mechanism for the maternofetal transport of Cbl during fetal development.-Arora, K., Sequeira, J. M., Quadros, E. V. Maternofetal transport of vitamin B12: role of TCblR/CD320 and megalin.
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Affiliation(s)
- Kaveri Arora
- Department of Cell Biology, School of Graduate Studies, State University of New York (SUNY) Downstate Medical Center, Brooklyn, New York, USA
| | - Jeffrey M Sequeira
- Department of Medicine, SUNY Downstate Medical Center, Brooklyn, New York, USA
| | - Edward V Quadros
- Department of Medicine, SUNY Downstate Medical Center, Brooklyn, New York, USA
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Yildirim ZK, Nexo E, Rupar T, Büyükavci M. Seven Patients With Transcobalamin Deficiency Diagnosed Between 2010 and 2014: A Single-Center Experience. J Pediatr Hematol Oncol 2017; 39:38-41. [PMID: 27824740 DOI: 10.1097/MPH.0000000000000685] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Transcobalamin deficiency (OMIM 275350) is a rare autosomal recessive disease presenting with nonspecific clinical features in early infancy. We report the clinical and laboratory manifestations of 7 children diagnosed with transcobalamin deficiency. All patients were admitted between 2 and 4 months of age with anemia, thrombocytopenia, and hyperhomocysteinemia. The most common complaints at admission were pallor, weakness, and poor feeding. Genetic analysis was performed in 5 patients and it revealed the same homozygous mutation. We initially treated all patients with intramuscular injections of a maximum of 1 mg cyanocobalamin (CN-Cbl) daily and with a final dose of 1 mg per week. Hemoglobin and platelet counts significantly decreased upon decrease or cessation of CN-Cbl therapy. The patients were reevaluated between 2 and 4 years of age and all had delay in speech and walking. In conclusion, 1 mg of intramuscular CN-Cbl every week suffices for hematological improvement but not for normal neurological development in patients who all had relapse due to decrease or cessation of treatment.
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