Sideroblastic anemia is caused by all except -

This is a refractory anaemia defined by the presence of many pathological ring sideroblasts in the bone marrow.These are abnormal erythroblasts containing numerous iron granules arranged in a ring or collar around the nucleus.Sideroblastic anaemia is diagnosed when 15% or more of marrow erythroblasts are ring sideroblasts.sideroblatic anemia iron containing inclusions are seen in RBCs . Here serum iron concention is seen to be markedly increased. Reference : Hoffbrand Hematology, 6th edition, pg 47. Exam preparatory manual for UGs by Ramdas Nayak Page no: 283