Macrocytic anemia occurs in all except
Copper - containing ceruloplasmin helps in iron transport. Copper is an integral part if ALA synthase enzyme which is used in haem synthesis.
Copper helps the uptake of iron by normoblasts. Thus in copper deficiency, RBC count is reduced, cell size is small but hemoglobin concentration is more or less normal.
So it results in microcytic normochromic anemia.
Thiamine deficiency
Liver disease
Orotic aciduria
Copper deficiency