Isolated Defect of Intestinal Iron Absorption in Siblings of Iron Deficiency Anemia

Abstract

Iron deficiency anemia (IDA) is the commonest type of anemia all over the world. It is easily treatable with oral iron therapy, but a minority of patients does remain unresponsive. This may be related to inappropriate compliance, manifest or occult blood loss, worm infestations, helicobacter infection, known malabsorption syndromes or paroxysmal nocturnal hemoglobinuria (PNH). We observed six such patients with non-responsive recurrent classical IDA who did not show any of the above conditions on specific investigations.Iron tolerance test (as an index of oral iron absorption) was performed on these patients. All of them showed negligible or no iron absorption, suggesting a defect in intestinal oral iron absorption as the cause of non-responsive IDA. This contention was supported by a dramatic response to parenteral iron therapy in all of them. Since the tests for known malabsorption syndromes were negative, it would be assumed that these subjects had an isolated defect in oral iron absorption that has been only scantily reported in the literature. Five of the six patients were siblings of two families. This raises the possibility of the defect in iron absorption to have a genetic connotation. Pending the complete work up for genetic studies, including the gene mutation for membrane bound serum protease type 6 (TMPRSS6) in these subjects and their families, this presentation is a short communication to expose and share our small experience of what looks to be an isolated defect in intestinal iron absorption.