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IRIDA syndrome in short
Iron-Refractory Iron Deficiency Anemia (IRIDA) syndrome is a rare autosomal recessive disorder of iron metabolism, marked by hypochromic, microcytic anemia that does not respond to oral iron supplementation and shows only partial improvement with parenteral iron therapy.
Synonyms
- Iron-refractory iron deficiency anemia
Prevalence: <1 / 1 000 000
Inheritance: Autosomal recessive
Age of onset: Infancy, Neonatal
How common is IRIDA syndrome?
- To date, 50 patients from 32 families of various ethnic backgrounds have been reported; however, the condition is likely underdiagnosed.
What are the symptoms of IRIDA syndrome?
Very Frequent Symptoms
- Decreased mean corpuscular volume
- Hypochromic microcytic anemia
- Iron deficiency anemia
Frequent Symptoms
- Decreased serum iron
- Decreased transferrin saturation
- Elevated circulating hepcidin concentration
Occasional Symptoms
- Anemic pallor
- Angular cheilitis
Rare Symptoms
- Alopecia
- Concave nail
Clinical description
- Most individuals with IRIDA exhibit no significant clinical symptoms apart from pallor, and typically experience normal growth and development.
- Anemia is usually mild and tends to be more pronounced during childhood. In cases of more severe anemia, symptoms may include fatigue, weakness, dizziness, and shortness of breath with exertion.
- Laboratory findings reveal hypochromic, microcytic anemia with markedly low serum iron and transferrin saturation levels, alongside normal or elevated serum hepcidin levels. Serum ferritin is generally within the normal range and may increase slightly following intravenous iron therapy.
What causes this condition?
- IRIDA syndrome is caused by mutations in the TMPRSS6 gene, which encodes Matriptase-2—a transmembrane serine protease crucial for suppressing hepcidin, the central regulator of iron balance in the body.
Genetic counseling
Transmission is autosomal recessive.
How is this condition diagnosed?
- Laboratory findings reveal hypochromic, microcytic anemia with markedly low serum iron and transferrin saturation, accompanied by normal or elevated serum hepcidin levels.
- Serum ferritin is typically within the normal range and may rise slightly following intravenous iron therapy. Diagnosis is confirmed through molecular genetic testing.
