Hereditary Hemochromatosis
http://www.100md.com
《新英格兰医药杂志》
To the Editor: Dr. Pietrangelo (June 3 issue)1 proposes that a liver biopsy be performed for diagnosis of suspected adult-onset hereditary hemochromatosis when first-line genetic testing does not reveal typical mutations and serum ferritin is persistently elevated. Two articles published this year2,3 show that magnetic resonance imaging (MRI) provides a useful and noninvasive diagnostic tool for quantification of hepatic iron concentrations. Gandon et al.2 found that a highly T2-weighted gradient-echo sequence was most sensitive, permitting detection of all clinically relevant cases of hepatic iron overload that exceeded 60 μmol per gram of liver, dry weight. We have used the MRI sequences proposed by Gandon4 and have obtained similar results with a high correlation index. In our work,3 the positive predictive value for hemochromatosis was 100 percent for estimated concentrations of more than 85 μmol per gram and the positive predictive value for iron overload was 100 percent for estimated concentrations of more than 58 μmol per gram. We think that magnetic resonance should be placed in the diagnostic algorithm before liver biopsy. Magnetic resonance may make it possible to avoid nearly all diagnostic liver biopsies.
Agustín Castiella, M.D.
Mendaro Hospital
20850 Mendaro, Spain
hmacasti@hmen.osakidetza.net
José M. Alustiza, M.D.
Osatek Donostia
20014 San Sebastian, Spain
José Artetxe, M.D.
Donostia Hospital
20014 San Sebastian, Spain
References
Pietrangelo A. Hereditary hemochromatosis -- a new look at an old disease. N Engl J Med 2004;350:2383-2397.
Gandon Y, Olivié D, Guyader D, et al. Non-invasive assessment of hepatic iron stores by MRI. Lancet 2004;363:357-362.
Alustiza JM, Artetxe J, Castiella A, et al. MR quantification of hepatic iron concentration. Radiology 2004;230:479-484.
Gandon Y. Iron and liver. (Accessed August 26, 2004, at http://www.radio.univ-rennes1.fr.)
Dr. Pietrangelo replies: MRI can undoubtedly be a useful noninvasive alternative to liver biopsy for quantifying the hepatic iron concentration. It may make it possible to avoid performing so many liver biopsies, such as those performed for workups of unexplained hyperferritinemia without clear evidence of liver disease1 (often encountered in nonhemochromatotic hereditary iron overload2), or for the follow-up of known iron-overload disorders. However, the purpose of the biopsy in the proposed algorithm in my article is not for the detection or quantification of hepatic iron overload but for the diagnosis of hereditary hemochromatosis. My definition of this disease may be at variance with that adopted by Dr. Castiella and colleagues.3 In my view, in patients with nondiagnostic genetic tests and persistent biochemical signs of iron overload, confirmation of clinically suspected hereditary hemochromatosis requires documentation not only of the presence but also of the typical cellular-distribution pattern of excess iron in hepatic tissues.4 Both can be assessed with biopsy, whereas current MRI techniques provide only the quantitative data.
Antonello Pietrangelo, M.D., Ph.D.
University of Modena
41100 Modena, Italy
pietrangelo.antonello@unimore.it
References
Gandon Y, Olivié D, Guyader D, et al. Non-invasive assessment of hepatic iron stores by MRI. Lancet 2004;363:357-362.
Pietrangelo A. The ferroportin disease. Blood Cells Mol Dis 2004;32:131-138.
Alustiza JM, Artetxe J, Castiella A, et al. MR quantification of hepatic iron concentration. Radiology 2004;230:479-484.
Tavill AS. Diagnosis and management of hemochromatosis. Hepatology 2001;33:1321-1328.
Agustín Castiella, M.D.
Mendaro Hospital
20850 Mendaro, Spain
hmacasti@hmen.osakidetza.net
José M. Alustiza, M.D.
Osatek Donostia
20014 San Sebastian, Spain
José Artetxe, M.D.
Donostia Hospital
20014 San Sebastian, Spain
References
Pietrangelo A. Hereditary hemochromatosis -- a new look at an old disease. N Engl J Med 2004;350:2383-2397.
Gandon Y, Olivié D, Guyader D, et al. Non-invasive assessment of hepatic iron stores by MRI. Lancet 2004;363:357-362.
Alustiza JM, Artetxe J, Castiella A, et al. MR quantification of hepatic iron concentration. Radiology 2004;230:479-484.
Gandon Y. Iron and liver. (Accessed August 26, 2004, at http://www.radio.univ-rennes1.fr.)
Dr. Pietrangelo replies: MRI can undoubtedly be a useful noninvasive alternative to liver biopsy for quantifying the hepatic iron concentration. It may make it possible to avoid performing so many liver biopsies, such as those performed for workups of unexplained hyperferritinemia without clear evidence of liver disease1 (often encountered in nonhemochromatotic hereditary iron overload2), or for the follow-up of known iron-overload disorders. However, the purpose of the biopsy in the proposed algorithm in my article is not for the detection or quantification of hepatic iron overload but for the diagnosis of hereditary hemochromatosis. My definition of this disease may be at variance with that adopted by Dr. Castiella and colleagues.3 In my view, in patients with nondiagnostic genetic tests and persistent biochemical signs of iron overload, confirmation of clinically suspected hereditary hemochromatosis requires documentation not only of the presence but also of the typical cellular-distribution pattern of excess iron in hepatic tissues.4 Both can be assessed with biopsy, whereas current MRI techniques provide only the quantitative data.
Antonello Pietrangelo, M.D., Ph.D.
University of Modena
41100 Modena, Italy
pietrangelo.antonello@unimore.it
References
Gandon Y, Olivié D, Guyader D, et al. Non-invasive assessment of hepatic iron stores by MRI. Lancet 2004;363:357-362.
Pietrangelo A. The ferroportin disease. Blood Cells Mol Dis 2004;32:131-138.
Alustiza JM, Artetxe J, Castiella A, et al. MR quantification of hepatic iron concentration. Radiology 2004;230:479-484.
Tavill AS. Diagnosis and management of hemochromatosis. Hepatology 2001;33:1321-1328.