Genetic approach to Wilson disease by use of the hereditary hepatitis LEC rats

LEC大鼠在出生后4个月左右突然发育。约30%的大鼠在1周内死于暴发性肝炎，其余的大鼠因慢性肝炎存活并随后发展为肝癌。最近发现，LEC大鼠肝脏中铜蓄积水平较高，血清铜蓝蛋白显著降低。LEC大鼠的这些临床和生化特征与肝豆状核变性非常相似，因此，我们提出将其作为肝豆状核变性的动物模型。我们将HTS定义为肝炎的基因标志。在本研究项目中，我们利用回交大鼠检验了肝豆状核变性的基因wne是否与hts同源：(1)利用lEC回交大鼠进行遗传分析，发现hts与人类的esd、rb1以及与wnD连锁的几个小卫星dna没有连锁，表明hts位于与rb1和esd所在的第15号染色体不同的染色体上。(2)由于在lEC大鼠中发现了血清铜蓝蛋白的总还原蛋白，我们从lEC中分离出了铜蓝蛋白基因，并且没有发现lec基因突变。对肝豆状核变性患者的HTS基因和WND基因的连锁分析表明，HTS基因和WND基因没有重组，表明WND基因是HTS基因的首选候选基因。因此，本研究结果提示LEC大鼠的肝炎可能是由于铜转运ATPase的缺陷引起的，可能是HTS基因的突变所致。

LEC rats develop abruptly about 4months after birth. Abot 30% of the rats die of fulminant hepatitis within 1 week, and remainder survive with chronic hepatitis and subsequently develop liver cancer. Recently, high levels of copper accumulation in the livers of LEC rats and gross reduction of serum ceruloplasmin have been found. These clinical and biochemical characteristics of LEC rats are very similar to Wilson disease, and therefore, we proposed the LEC as an animal model for Wilson disease. We defined hts as the gene symbol for the hepatitis. In this research project, we have examined whether the gene, WNE, for Wilson disease is homologous to the hts by use of backcross rats :(1) Genetic analysis by use of backcross rats of LEC showed no linkage between hts and genes for ESD, RB1, and several minisatellite DNAs which linked to the WND in human, indicating that the hts locates on a different chromosome from no.15 on which RB1 and ESD are located.(2) As gross reductin of serum ceruloplasmin was found in LEC rats, we have isolated the gene for ceruloplasmin from the LEC, and found no mutation in the gene of LEC, suggesting that the copper accumulatino is not due to alteration of the ceruloplasmin gene.Linkage analysis of the hts and WND for Wilson disease showed the identical segregation pattern and no recombination demonstrating that the WND gene is a prime candidate for hts.Thus, the results obtained here suggest that the hepatitis of LEC rats may be caused by a defect in a copper transporting ATPase, possibly due to mutation of hts.