Thiamine responsive anaemia: a study of two further cases

Abstract

A brother and sister of Pakistani origin suffered from sensorineural deafness, diabetes mellitus and a macrocytic anemia. Their bone marrows showed megaloblastic erythropoiesis and contained many ringed sideroblasts. EM studies of the bone marrow revealed Fe-laden mitochondria in many erythroblasts, nonspecific anbormalities indicative of dyserythropoiesis in some erythroblasts and evidence of ineffective erythropoiesis. The deoxyuridine suppression test indicated that the megaloblastic changes were not caused by an impairment of the methylation of deoxyuridylate. Studies of nucleic acid synthesis in the bone marrow cells showed that the rate of incorporation of [3H]thymidine into DNA was increased and that the rates of incorporation of [14C]glycine and [14C]adenine into both DNA and RNA were essentially within the normal range. The anemia did not respond to therapy with hydroxocobalamin, folic acid or pyridoxine, but responded to 25 mg thiamin, daily, by mouth. In one of the cases, a post-thiamin marrow aspirate showed a considerable improvement in both the megaloblastic and sideroblastic changes.