Steroid-responsive functional B12 deficiency in association with transcobalamin II polymorphism 776C --> G.
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.
Gale
Daniel P
DP
Department of Neurology, St Mary's Hospital, London, UK. dannyg@doctors.org.uk
Cobbold
Jeremy F
JF
Chataway
Jeremy
J
D000368:Aged; D000749:Anemia, Megaloblastic / Q000097:blood / Q000150:complications / Q000188:drug therapy / Q000235:genetics; D005260:Female; D006579:Heterozygote; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D013256:Steroids / Q000008:administration & dosage; D014155:Transcobalamins / Q000235:genetics*; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000150:complications / Q000188:drug therapy / Q000235:genetics*
D013256:Steroids; D014155:Transcobalamins