Megaloblastic anemia may be caused by all the following except

Ref Harrison 19 th ed pg 640 Table,;128-1 Causes of Megalobla stic Anemia Cobalamin deficiency or abnormalities of cobalamin metabolism Folate deficiency or abnormalities of folate metabolism Therapy with antifolate drugs (e.g., methotrexate) Independent of either cobalamin or folate deficiency and refractory to cobalamin and folate therapy: Some cases of acute myeloid leukemia, myelodysplasia Therapy with drugs interfering with synthesis of DNA (e.g., cytosine arabinoside, hydroxyurea, 6-mercaptopurine, azidothymidine ) Orotic aciduria (responds to uridine) Thiamine-responsive