Congenital intrinsic factor deficiency (IFD) is a rare disorder of vitamin B12 (cobalamin) absorption that is characterized by megaloblastic anemia and neurological abnormalities. The disease is MONDO_0009852 (hereditary intrinsic factor deficiency). Also known as: IFD, congenital intrinsic factor deficiency, congenital pernicious anaemia, congenital pernicious anemia, gastric intrinsic factor deficiency, hereditary juvenile megaloblastic anaemia due to intrinsic factor deficiency, hereditary juvenile megaloblastic anemia due to intrinsic factor deficiency.