Halliday J W
Queensland Institute of Medical Research, Bancroft Centre, Royal Brisbane Hospital, Queensland, Australia.
Nutr Rev. 1998 Feb;56(2 Pt 2):s30-7; discussion s54-75. doi: 10.1111/j.1753-4887.1998.tb01684.x.
Although iron is an essential dietary requirement, the amount absorbed by the body is well regulated and depends on body iron stores and on dietary iron availability. There is very little iron excreted under normal conditions. Iron deficiency is a worldwide problem but iron overload, as seen in the inherited disease, hemochromatosis, is a major cause of morbidity in some Caucasian populations. This is a problem particularly where there is an adequate dietary iron intake and especially in males. A mutation has recently been described in an MHC Class l-like gene (HFE) that encodes for a protein (HFE) of 343 amino acids. The molecule contains a signal sequence peptide-binding region, alpha, and alpha(2) domains, and an immunoglobulinlike alpha(3) domain, in addition to a transmembrane region and a small cytoplasmic tail. It is a candidate gene for hemochromatosis. Several possibilities as to the function of this gene and the corresponding protein have been suggested but none has yet been confirmed. The mutation has been detected by several different groups in 80%-100% of subjects with the disease. However, in one study, 18%-20% of patients with the mutation did not exhibit significant iron overload. The discovery of this gene has important implications for both clinical studies and the elucidation of the pathways of iron metabolism.
尽管铁是饮食中的必需元素，但人体对其吸收量受到严格调控，且取决于体内铁储备和膳食中铁的可利用性。在正常情况下，铁的排泄量极少。缺铁是一个全球性问题，但铁过载，如遗传性疾病血色素沉着症中所见，是某些白种人群发病的主要原因。在膳食铁摄入量充足的情况下，尤其是男性，这一问题尤为突出。最近在一个类似MHC I类的基因（HFE）中发现了一种突变，该基因编码一种由343个氨基酸组成的蛋白质（HFE）。除跨膜区和一小段胞质尾巴外，该分子还包含一个信号序列、肽结合区、α和α(2)结构域以及一个免疫球蛋白样的α(3)结构域。它是血色素沉着症的一个候选基因。关于该基因及其相应蛋白质的功能提出了几种可能性，但均未得到证实。几个不同的研究小组在80%-100%的患病个体中检测到了这种突变。然而，在一项研究中，18%-20%携带该突变的患者并未表现出明显的铁过载。该基因的发现对临床研究和铁代谢途径的阐明都具有重要意义。
