Two nonsense mutations in the TMPRSS6 gene in a patient with microcytic anemia and iron deficiency.

Genetic causes of hypochromic microcytic anemia include thalassemias and some rare inherited diseases such as DMT1 deficiency. Here, we show that iron deficiency anemia with poor intestinal absorption and defective iron utilization of IV iron is caused by inherited mutations in TMPRSS6, a liver-expressed gene that encodes a membrane-bound serine protease of previously unknown role that was recently reported to be a regulator of hepcidin expression.