Malabsorption and defective utilization of iron in three siblings.

Three siblings had iron deficiency anemia without evidence of reduced iron intake or gastrointestinal blood loss. They failed to respond to oral iron therapy, and malabsorption of oral medicinal iron was demonstrated in two of the children. All three had a partial but incomplete hematologic response to intramuscular iron dextran treatment. There was no evidence for other well-defined causes of hypochromic microcytic anemia or for a generalized disorder of intestinal absorption. These three patients appear to have a familial disorder characterized by impaired iron absorption and utilization, similar to that observed in the mk/mk mouse.