Steroid‐responsive functional B12 deficiency in association with transcobalamin II polymorphism 776C→G

Abstract

We present a case of intracellular vitamin B12 deficiency presenting with confusion, subacute combined degeneration of the cord, megaloblastic anaemia and intrinsic factor antibodies in the serum. Diagnosis was delayed by a normal serum B12 level and was confirmed by a grossly elevated serum homocysteine. There was a dramatic response to steroids. The patient was heterozygous for the transcobalamin (TC) II polymorphism 776C --> G. This case demonstrates the importance of functional assessment of intracellular B12 activity (e.g. serum homocysteine) in excluding B12 deficiency, the role of steroids in pernicious anaemia and a possible clinical correlation of a TCII polymorphism.

Functional vitamin B12 deficiency

“…Gale and colleagues reported a 72-year-old patient presenting with confusion, clinical subacute combined degeneration of the cord and megaloblastic anaemia 4. Normal serum B12 levels were found despite later detection of intrinsic factor antibodies in the serum.…”

Vitamin B₁₂-Responsive Pancytopenia Mimicking Myelodysplastic Syndrome

“…Pseudo-thrombotic microangiopathy can be related to vitamin B 12 deficiency [3,4]. Pernicious anemia, a common cause of vitamin B 12 deficiency, is clinically responsive to steroid therapy, which is likely due to suppression of an underlying autoimmune process [5,6]. Anemia and other abnormal hematologic findings typically improved within 1–2 weeks of parenteral vitamin B 12 supplementation, confirming the vitamin B 12 -deficient state in these patients regardless of the serum vitamin B 12 level.…”