Iron-refractory iron deficiency anemia is one of many types of anemia, which is a group of conditions characterized by a shortage of healthy red blood cells. This shortage prevents the blood from carrying an adequate supply of oxygen to the body's tissues.

Iron-refractory iron deficiency anemia results from an inadequate amount (deficiency) of iron in the bloodstream. It is described as "iron-refractory" because the condition is totally resistant (refractory) to treatment with iron given orally and partially resistant to iron given in other ways, such as intravenously (by IV). In people with this form of anemia, red blood cells are abnormally small (microcytic) and pale (hypochromic). The symptoms of iron-refractory iron deficiency anemia can include tiredness (fatigue), weakness, pale skin, and other complications. These symptoms are most pronounced during childhood, although they tend to be mild. Affected individuals usually have normal growth and development.

Although iron deficiency anemia is relatively common, the prevalence of the iron-refractory form of the disease is unknown. At least 50 cases have been described in the medical literature. Researchers suspect that iron-refractory iron deficiency anemia is underdiagnosed because affected individuals with very mild symptoms may never come to medical attention.

Mutations in the TMPRSS6 gene cause iron-refractory iron deficiency anemia. This gene provides instructions for making a protein called matriptase-2, which helps regulate iron levels in the body. TMPRSS6 gene mutations reduce or eliminate functional matriptase-2, which disrupts iron regulation and leads to a shortage of iron in the bloodstream. Iron is an essential component of hemoglobin, which is the molecule in red blood cells that carries oxygen. When not enough iron is available in the bloodstream, less hemoglobin is produced, causing red blood cells to be abnormally small and pale. The abnormal cells cannot carry oxygen effectively to the body's cells and tissues, which leads to fatigue, weakness, and other symptoms of anemia.

Genetic Testing Information

• Genetic Testing Registry: Iron-refractory iron deficiency anemia

Genetic and Rare Diseases Information Center

• IRIDA syndrome

Patient Support and Advocacy Resources

• National Organization for Rare Disorders (NORD)

Clinical Trials

• ClinicalTrials.gov

Catalog of Genes and Diseases from OMIM

• IRON-REFRACTORY IRON DEFICIENCY ANEMIA; IRIDA

Scientific Articles on PubMed

• PubMed

• Brissot P, Bardou-Jacquet E, Jouanolle AM, Loreal O. Iron disorders of genetic origin: a changing world. Trends Mol Med. 2011 Dec;17(12):707-13. doi: 10.1016/j.molmed.2011.07.004. Epub 2011 Aug 20. Citation on PubMed
• De Falco L, Sanchez M, Silvestri L, Kannengiesser C, Muckenthaler MU, Iolascon A, Gouya L, Camaschella C, Beaumont C. Iron refractory iron deficiency anemia. Haematologica. 2013 Jun;98(6):845-53. doi: 10.3324/haematol.2012.075515. Citation on PubMed or Free article on PubMed Central
• De Falco L, Totaro F, Nai A, Pagani A, Girelli D, Silvestri L, Piscopo C, Campostrini N, Dufour C, Al Manjomi F, Minkov M, Van Vuurden DG, Feliu A, Kattamis A, Camaschella C, Iolascon A. Novel TMPRSS6 mutations associated with iron-refractory iron deficiency anemia (IRIDA). Hum Mutat. 2010 May;31(5):E1390-405. doi: 10.1002/humu.21243. Citation on PubMed
• Finberg KE, Heeney MM, Campagna DR, Aydinok Y, Pearson HA, Hartman KR, Mayo MM, Samuel SM, Strouse JJ, Markianos K, Andrews NC, Fleming MD. Mutations in TMPRSS6 cause iron-refractory iron deficiency anemia (IRIDA). Nat Genet. 2008 May;40(5):569-71. doi: 10.1038/ng.130. Epub 2008 Apr 13. Citation on PubMed or Free article on PubMed Central