TMPRSS6 and IRIDA syndrome: IRIDA is a hereditary autosomal recessive anemia in which mutations in the TMPRSS6 gene, which encodes matriptase II, are responsible for hepcidin levels that are inappropriately high in correlation to the low levels of free iron in these patients.4,5 Until now, 51 families and 74 patients of different ethical origins have been identified representing a total of 58 different mutations in the TMPRSS6 gene.8 IRIDA’s prevalence is thought to be less than 1:1 000 000,6 although it may be underestimated.