Inherited Lack of Transcobalamin II in Serum and Megaloblastic Anaemia: a Further Patient

Abstract

A patient, unrelated to patients previously described, with inherited lack of the vitamin B12 binding protein transcobalamin II was studied. Severe hematological abnormalities were found within a few weeks of birth, but he responded to treatment with vitamin B12 and folic acid. He was maintained in partial remission with such treatment until adolescence, except in early childhood when only folic acid was given and he suffered severe neurological deterioration. At 18 yr he was admitted to a hospital because of convulsions. The deoxyuridine suppression test showed intracellular deficiency of B12 despite a normal serum B12 and normal Hb concentration. His serum failed to promote the uptake of radioactive B12 by bone marrow cells, and analysis of serum B12 binding proteins demonstrated the lack of transcobalamin II. Treatment with injections of 1000 .mu.g of B12 3 times weekly corrected the abnormality shown in the deoxyuridine suppression test. With this treatment, and changes in anticonvulsive therapy, he remains healthy without occurrence of further convulsions, and is hematologically normal.