We present a case of intracellular vitamin B12 deficiency presenting with confusion, subacute combined degeneration of the cord, megaloblastic anaemia and intrinsic factor antibodies in the serum.
Several syndromes present with megaloblastic anemia such as congenital megaloblastic anemia due to intrinsic factor defect and juvenile megaloblastic anemia with proteinuria due to defects in the cubilin or the amnionless protein.
Congenital intrinsic factor (IF) deficiency is a disorder characterized by megaloblastic anemia due to the absence of gastric IF (GIF, GenBank NM_005142) and GIF antibodies, with probable autosomal recessive inheritance.