Finberg et al. (2008) referred to this phenotype as iron-refractory iron deficiency anemia (IRIDA) and reviewed the key features: a congenital hypochromic, microcytic anemia; a very low mean corpuscular erythrocyte volume; a low transferrin saturation; abnormal iron absorption characterized by no hematologic improvement following treatment with oral iron; and abnormal iron utilization characterized by a sluggish, incomplete response to parenteral iron. The authors noted that although urinary levels of hepcidin (606464) are typically undetectable in individuals with iron deficiency, in 5 individuals with IRIDA urinary hepcidin/creatinine ratios were within or above the normal range.

Iron overload (IO) is characterized by the onset of increased systemic iron levels apparent in mid-adulthood. Laboratory studies show increased serum ferritin, normal or high transferrin saturation, increased liver iron content, and inappropriately low or normal levels of hepcidin. Presence of a BMP6 mutation confers susceptibility to the disorder, but additional factors, including alcohol consumption, increased body weight, and possibly HFE gene (613609) variants, may contribute to the severity of the manifestations (Daher et al., 2016; Piubelli et al., 2017).