Transcobalamin II Deficiency in Four Cases with Novel Mutations

Abstract

INTRODUCTION: Transcobalamin II deficiency is one of the rare causes of inherited vitamin B12 disorders in which the patients have characteristically normal or high vitamin B12 levels related to the transport defect of vitamin B12 into the cell, ending up with intracellular cobalamin depletion and high homocysteine and methylmalonic acid levels. METHODS: Herein, we describe the findings at presentation of four patients who were diagnosed to have transcobalamin II deficiency with novel mutations. RESULTS: These patients with transcobalamin II deficiency were found to have novel mutations, of whom 2 had the same large deletion (homozygous c.1106+1516-1222+1231del). DISCUSSION AND CONCLUSION: Transcobalamin II deficiency should be considered in differential diagnosis of any infant with pancytopenia, failure to thrive, diarrhea, and vomiting.

Keywords

• vitamin b12
• transcobalamin ii
• novel mutation
• novel deletion
• vacuolizatio