The neurologic aspects of transcobalamin II deficiency

Br J Haematol. 1992 Jan;80(1):117-20. doi: 10.1111/j.1365-2141.1992.tb06410.x.


Thirty-four symptomatic cases of inherited transcobalamin II (TCII) deficiency were analysed in order to determine the frequency and nature of neurologic manifestations. In no instance was there definite evidence of a neurologic disorder at the time of presentation as a young infant. One child of 2 1/2 years transiently lost deep tendon reflexes at a time of suboptimal treatment. A syndrome of mental retardation and other neurologic manifestations was observed in three cases, all with the following in common: (1) an extended duration of illness of 2-17 years; (2) inadequate or not treatment with Cbl; (3) treatment with folic of folinic acid. TCII deficiency rarely if ever presents with neurologic manifestations. However, neurologic disorders can be produced subsequently by improper treatment.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Central Nervous System Diseases / etiology
  • Folic Acid / therapeutic use
  • Humans
  • Infant
  • Infant, Newborn
  • Intellectual Disability / etiology
  • Leucovorin / therapeutic use
  • Nervous System Diseases / etiology*
  • Time Factors
  • Transcobalamins / deficiency*
  • Vitamin B 12 / therapeutic use


  • Transcobalamins
  • Folic Acid
  • Vitamin B 12
  • Leucovorin