● ● ● CLINICAL TRIALS ANDOBSERVATIONS Comment on Lok et al, page 20 Iron overload in Asia

In a remarkable study in this issue ofBlood, Lok and colleagues describe the geno-typic and phenotypic characteristics of hereditary hemochromatosis in 42 cases in 8 distinct families of Asian origin.1 Hemochromatosis is a hereditary disordercharacterized by excessive iron absorp-tion in the diet, leading to iron overload and toxicity to various organs. It is a genetically heterogeneousdisease.HFEhemochromatosis is themost common formof hemochromatosis in populations ofNorthernEuropean origin. In addition, other non-HFEhemochromatosis mutations are increasingly being recognized in NorthernEuropeans.By contrast, hemochro-matosis inAsia is believed to beuncommonand is notwell understood. Part of the difficulty rec-ognizing aphenotype suggestive of hereditary hemochromatosis inAsia is the highprevalence of other hemoglobindisorders such as thalasse-mia resulting in secondary iron overload, and, conversely, the possiblemasking of hereditary iron overloadby ahighprevalence of coexistent irondeficiency on the other. None of the patients described by Lok et al have the commonHFE hemochromatosis. Novel mutations in genes encoding hemojuve-lin (HJV), hepcidin (HAMP), and ferroportin (SLC40A1) were identified in 8 families fro