Transcobalamin deficiency — a rare genetic defect in transportation of cobalamin; case report

• Published in: Annals of hematology Vol. 103; no. 8; pp. 3243 - 3246
• Main Authors: Iqbal, Neelofar, Meghani, Marium Ali, Khalid, Wajeeha, Ansari, Ali Hussain, Ansari, Muhammad Usman Hussain, Ansari, Saqib Hussain
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2024; Springer Nature B.V
• Subjects: Acids; Anemia; Antibiotics; Biopsy; Bone marrow; Case Report; Case reports; Children & youth; Fever; Genetic testing; Hematology; Infections; Medicine; Medicine & Public Health; Mutation; Oncology; Patients; Proteins; Vitamin B; Vitamin deficiency; Megaloblastic anemia; Transcobalamin II deficiency; Vitamin B12; Next generation sequencing; Pancytopenia
• ISSN: 0939-5555; 1432-0584; 1432-0584
• DOI: 10.1007/s00277-024-05878-7

Background Vitamin B12 is primarily transported from plasma to cells by Transcobalamin. Deficiency of Transcobalamin is a rare autosomal recessive disorder that results in unavailability of cobalamin in cells and accumulation of homocysteine and methylmalonic acid. Case Report We report a case of a 2-year-old male child with persistent pancytopenia, recurrent infections, and megaloblastic anemia. Next-generation sequencing identified a novel variant in exon 8 of TCN2 gene. Substantial improvement has been observed following administration of high doses of parenteral methylcobalamin. Conclusion In patients with unresolved pancytopenia and megaloblastic anemia, Transcobalamin deficiency should be investigated and treated promptly to prevent any irreversible and harmful outcome.