Rosmorduc O, Poupon R, Nion I, Wendum D, Feder J, Béréziat G, Hermelin B
Service d'Hépatogastroentérologie, Hôpital Saint-Antoine and Université Pierre et Marie Curie, Paris, France.
Gastroenterology. 2000 Oct;119(4):1075-86. doi: 10.1053/gast.2000.18146.
BACKGROUND & AIMS: Hereditary hemochromatosis is associated with C282Y homozygosity. Some heterozygotes may also present with abnormal iron parameters. However, the precise role of H63D and C282Y mutations in iron overload is poorly understood. We investigated the level of expression of the mutated and unmutated HFE alleles in these heterozygous patients.
We studied the expression of HFE messenger RNAs in peripheral blood mononuclear cells from 34 heterozygotes using reverse-transcription polymerase chain reaction (PCR) followed by enzymatic digestion or sequence analysis of the PCR products, which allows relative quantification of mutated and unmutated transcripts. HFE proteins were quantified by Western blotting in Epstein-Barr virus-immortalized lymphocyte extracts from 2 C282Y and H63D homozygotes and a compound heterozygote.
(187C > G; H63D) mutated transcripts predominated in H63D and compound heterozygotes and the normal transcripts in C282Y heterozygotes. The amount of HFE protein was increased in the H63D homozygotes and the compound heterozygote compared with the C282Y homozygotes. In addition, we found a new mutation at codon 282 (C282S) associated with severe iron overload.
We demonstrate the existence of differential allelic expression of the HFE alleles, suggesting that the (187C > G; H63D) mutation plays a role in the disease expression in H63D heterozygotes, in particular when associated with environmental or host factors.
遗传性血色素沉着症与C282Y纯合子相关。一些杂合子也可能出现铁参数异常。然而，H63D和C282Y突变在铁过载中的确切作用尚不清楚。我们研究了这些杂合子患者中突变和未突变的HFE等位基因的表达水平。
我们使用逆转录聚合酶链反应（PCR），随后对PCR产物进行酶切或序列分析，研究了34名杂合子外周血单个核细胞中HFE信使核糖核酸的表达，这可以对突变和未突变的转录本进行相对定量。通过蛋白质免疫印迹法对来自2名C282Y和H63D纯合子以及1名复合杂合子的爱泼斯坦-巴尔病毒永生化淋巴细胞提取物中的HFE蛋白进行定量。
（187C>G；H63D）突变转录本在H63D和复合杂合子中占主导，而正常转录本在C282Y杂合子中占主导。与C282Y纯合子相比，H63D纯合子和复合杂合子中的HFE蛋白量增加。此外，我们在第282密码子处发现了一个与严重铁过载相关的新突变（C282S）。
我们证明了HFE等位基因存在差异等位基因表达，表明（187C>G；H63D）突变在H63D杂合子的疾病表达中起作用，特别是与环境或宿主因素相关时。
