A Case of Juvenile Pernicious Anemia: Study of the Effects of Folic Acid and Vitamin B₁₂

Observations on a 4-year-old boy with Addisonian pernicious anemia have been presented. Noteworthy clinical features included the onset of glossitis at the age of 4 months, followed by anemia severe enough to require hospitalization at the age of 1 year. Relapse occurred in the absence of specific therapy with vitamin B₁₂ and was completely unaffected by the administration of folic acid.

Studies with radioactive vitamin B₁₂ demonstrated that almost all of the compound administered by mouth was unabsorbed and was recovered in the stools. When the vitamin was given simultaneously with a concentrate of intrinsic factor, however, approximately 70 per cent was absorbed. Furthermore, the child’s gastric juice, when mixed with radioactive vitamin B₁₂ and fed to an adult with pernicious anemia in relapse, failed to enhance the latter’s absorption of the vitamin. The failure of our patient to absorb the vitamin alone, but his ability to do so when it was administered with intrinsic factor concentrate, was also confirmed by the "Schilling test," in which a proportion of the absorbed radioactive vitamin was "flushed" into the urine by parenteral injection of one milligram of conventional vitamin B₁₂.

Of special interest was the occurrence in the urine of an unidentified derivative of tetrahydrofolic acid, derived from orally administered pteroylglutamic acid. The presence of this compound in the urine was demonstrated chromatographically when the patient was critically ill with his disease prior to treatment with vitamin B₁₂. Subsequent to therapy with vitamin B₁₂, while the administration of folic acid was continued, the abnormal metabolite of folic acid could not be found in the urine. Similarly, the administration of folic acid did not lead to the appearance of this metabolite in the urine at a time when, after more than two years without specific therapy, a hematological relapse occurred that was much less severe than that previously observed. The implications of these observations, with respect to the metabolic interrelationships of folic acid and vitamin B₁₂, are discussed.

Of further interest were the findings of strongly acid gastric juice containing much mucus and free hydrochloric acid. A fairly normal gastric mucosa was demonstrated by biopsy. The meaning of these unusual findings is discussed and an hypothesis to account for them is offered. The probable sequence of events in these patients from childhood to the development of anemia, usually in later life, is set forth.