Thiamine-responsive megaloblastic anemia

Abstract

An 11-year-old Caucasian girl is presented who had a megaloblastic anemia responsive only to thiamine. Other abnormalities included diabetes mellitus, aminoaciduria, and sensorineural deafness. Initially the anemia, refractory to vitamin B 12 and folic acid therapy, responded to administration of a multiple vitamin preparation. Vitamin supplementation was withdrawn followed by a recurrence of anemia 3½ months later. The implicated vitamins were then administered sequentially. A reticulocytosis followed administration of thiamine. Anemia again recurred 4 months after cessation of vitamin supplementation. On this occasion the anemia was corrected by the oral administration of 20 mg. thiamine daily. Thiamine blood levels and activities of 3 thiamine-dependent enzymes of the patient's blood cells were normal, excluding a generalized defect of thiamine metabolism. The patient therefore appeared to have a thiamine-dependent megaloblastic anemia. This represents the first demonstration of a role for this vitamin in DNA metabolism.