Intracellular localization of the Menkes and Wilson''s disease proteins and their role in intracellular copper transport

Copper is a heavy metal ion essential for the activity of a variety of enzymes in the body. In excess, copper is a very toxic ion and therefore efficient regulation of its metabolism is required. This is dramatically illustrated by the genetic disorders X-linked Menkes disease and autosomal recessive Wilson's disease. In 1993, both the Menkes and Wilson's genes were isolated and it was found that these genes encode homologous cation copper transporting P-type ATPase proteins. The Menkes protein (ATP7A) is expressed in most tissues, except liver. In contrast, the Wilson's protein (ATP7B) is abundantly expressed in liver. Intracellular localization of those proteins was investigated. Both ATP7A and ATP7B are localized in the trans-Golgi network and post-Golgi vesicular compartment (PGVC) in the cell. This intracellular localization was altered by the copper content present in the cell. This result may support the hypothesis that ATP7A and ATP7B are involved in cellular copper transport and those proteins could be suitable models for elucidating intracellular copper metabolism.     

Molecular analysis and diagnosis in Japanese patients with Wilson''s disease

BACKGROUND: Wilson's disease is characterized by the toxic accumulation of copper in the liver, brain, cornea and other organs. It is caused by both impaired excretion via the bile and impaired incorporation of copper into ceruloplasmin in the liver. The Wilson's disease gene (ATP7B) has been cloned as a putative copper-transporting P-type ATPase gene. We therefore analysed mutations of ATP7B in Japanese patients with Wilson's disease. METHODS: Twenty-three Japanese patients with Wilson's disease were investigated. In all patients, the ATP7B coding sequence, including exon-intron junctions, was analysed by restriction endonuclease digestion, mutation detected enhancement gel electrophoresis and/or direct sequencing analysis of amplified fragments. RESULTS: Thirteen mutations were identified, including seven missense mutations, four detections, one insertion and one exon skipping in the coding region. The most common mutations were 2874deletion(del)C in exon 13 and arginine (Arg)778 leucine (Leu) in exon 8. DISCUSSION: None of the observed mutations, except for 2302insertion(ins)C, have been previously detected in either European or North American patients. We conclude that the mutation spectrum of Wilson's disease may thus indicate a population-dependent pattern. Based on the population-dependent manner of the occurrence of ATP7B gene mutations, it may be possible to establish a molecular diagnosis system. A molecular diagnosis system is considered to be very effective for making a definitive diagnosis in very young patients and for also detecting carriers.     

Identification of two novel mutations in the <Emphasis Type="Italic">ATP7B</Emphasis> gene that cause Wilson’s disease

Background:Wilson's disease is an autosomal recessive disorder characterized by liver disease and/or neurologic deficits due to copper accumulation and is caused by pathogenic mutations in the ATP7B gene.Methods:Two unrelated Chinese patients born to nonconsanguineous parents who were diagnosed with earlyonset Wiison's disease.DNA sequencing and bioinformation analysis were conducted.Results:We have identified four mutations in two family trios,of which two were novel,namely,c.3028A＞G(p.K1010E) and c3992T＞G (p.Y1331X),in each patient.Conclusions:Gene testing is playing an important role in diagnosis of Wilson's disease.The early-onset of Wilson's disease is apparently not associated with P-ATPase domain in the ATP7B protein.Our findings further widen the spectrum of mutations involving the ATP7B gene.     

Wilson's disease patients with normal ceruloplasmin levels

Wilson's disease, an inborn defect of copper metabolism, is a fatal disease unless specific treatment is given. Hepatic presentation mimics almost all kinds of liver disease and the diagnosis is sometimes problematic. The diagnosis is based on clinical findings, family history, presence of Kayser-Fleischer rings, and results of key laboratory tests such as low serum ceruloplasmin level, increased urinary copper excretion and hepatic copper content. We report four patients with Wilson's disease with hepatic manifestations with unknown there were difficulties in making the diagnosis because of normal serum ceruloplasmin levels. Inspite of normal ceruloplasmin levels and absence of Kayser-Fleischer rings, strong family history suggested Wilson's disease and the diagnosis was confirmed by increased urinary and hepatic copper amounts.     

Hepatocellular carcinoma in Wilson's disease: a rare association in childhood

Wilson's disease is a hereditary disorder of copper metabolism that results in the accumulation of copper in the body, primarily in the liver, brain, and cornea. Hepatocellular carcinoma, in contrast to other causes of cirrhosis, is seldom associated with Wilson's disease. We present a 12-yr-old boy with Wilson's disease in whom hepatocellular carcinoma was incidentally diagnosed in the pathologic specimen examined after liver transplantation.     

Direct diagnosis of Wilson disease by molecular genetics

In 3 children with chronic liver disease, although multiple studies of copper metabolism were normal, which made the diagnosis of Wilson disease unlikely, analysis of ATP7B gene showed disease causing mutations in all. Molecular diagnosis should be considered in children with enigmatic liver disease, especially those with features of nonalcoholic fatty liver disease.     

Inherited copper toxicity in Long-Evans cinnamon rats exhibiting spontaneous hepatitis: a model of Wilson's disease.

The copper concentrations in organs of developing Long-Evans Cinnamon (LEC) rats (2 d to 13 mo) were measured to elucidate the pathogenesis of their hereditary hepatitis. Hepatic copper contents of LEC rats were significantly higher than those of control rats (26 to 92 times higher). The subcellular distribution of hepatic copper indicated that the nuclear and large granular fractions had been saturated and the cytosol fraction contained about 70% of all the hepatic copper in LEC rats. The serum concentrations of copper and ceruloplasmin were significantly lower than those of control rats from the 4th wk (10-12% and 5-19%, respectively). Copper contents in kidney of LEC rats did not exhibit an increase over those of control rats until 12 wk, but then increased to nearly 40 times higher during fulminant hepatic failure. Accumulation of copper was not detected in the brain or small intestines of LEC rats until 13 mo. The hepatic copper concentration, its subcellular distribution, and serum copper concentration of F1 rats (LEC x Long-Evans Agouti) exhibited the same levels as those of Long-Evans Agouti rats. In addition to their similarity concerning inheritance of autosomal recessive means and clinical course, we found causality relating copper accumulation to the pathogenesis of the disease. We propose that LEC rats will be the most promising animal model for the study of Wilson's disease.     

Severe hepatic Wilson's disease in preschool-aged children

A 3-year-old girl presented with hemolytic anemia, hepatosplenomegaly, ascites, and evidence of decompensated chronic liver disease. Genotypic DNA analysis revealed that the patient was homozygous for a splice site mutation now designated IVS4-1:G>C, expected to destroy completely the functional gene product of ATP7B, the gene responsible for Wilson's disease. We suggest that this severe mutation caused very early liver disease. Wilson's disease should be considered in the differential diagnosis of established liver disease in the preschool-aged child.     

亲体部分肝移植治疗小儿肝豆状核变性病

目的：通过亲体部分肝移植的方法治疗小儿肝豆状核变性病（Wilson‘s病），探讨Wilson‘s病的根治方法。方法：对术前均明确诊断为Wilson‘s病的患儿（男1例，女4例）施行亲体部分肝移植，患儿平均年龄9岁，本组供肝者均为患儿母亲，Child分级：B组4例，C级1例，除1例患儿血型为B型，供体血型为O型外，其余均为供受体血型相同，结合临床资料对本组所有Wilson‘s病患儿进行回顾性分析。结果：所有供，受体手术顺利，术后恢复良好，5例Wilson‘s病患儿术后3周患儿进行回顾性.分析结果：所有供，受体手术顺利，术后恢复良好，5例Wilson‘s病患儿术后3周肝功能恢复正常，复查铜氧化酶均正常，K－F环均不同程度变浅，神经系统症状有所好转，术后并发症，1例出现肝动脉栓塞（术后第6d再次行减体积肝移植），术后分别随访12．5个月，11个月，10个月，9个月和7．5个月，现均已康复出院。结论：亲体部分肝移植是根治Wilson‘s病等代谢性疾病的有效方法。     

儿童肝豆状核变性临床表型及ATP7B基因突变关联性分析

目的 了解汉族儿童肝豆状核变性(WD) 患儿的临床表型与ATP7B基因突变的相关性。方法 以2005年7月至2012年12月就诊于复旦大学附属儿科医院确诊WD患儿为研究对象,按起病部位分为肝病型和神经型,以临床表现分为临床型和亚临床型。采用PCR技术扩增ATP7B基因全部外显子并直接测序。提取临床表型和基因型的信息;分析两者之间的相关性。结果 52个无亲缘关系家庭的53例WD患儿进行分析。肝脏损害52例（98.5%）。肝病型41例,神经型12例;临床型19例,亚临床型34例。①肝病型ALT升高明显;神经型24 h尿铜水平、胆汁酸水平和K-F环阳性率均显著高于肝病型;亚临床型起病年龄、ALT或AST异常率显著高于临床型;24 h尿铜水平、胆汁酸升高比例和K-F环阳性率显著低于临床型。②53例WD患儿ATP7B基因外显子序列分析发现致病性突变等位基因97个,突变频率为91.5%。纯合突变8例,复合杂合36例,杂合突变9例。错义突变23种,插入/缺失突变8种,无义突变2种,剪接突变3种。③错义突变与非错义突变,纯合突变与杂合突变患儿在起病年龄、K-F环阳性率、铜蓝蛋白水平、24 h 尿铜水平和ALT、AST异常率等方面差异无统计学意义。④3种高发突变p.Arg778Leu（35.0%,34/97）、p.Pro992Leu (15/97,15.5%)和p.Ala874Val/Pro(5/97,5.2%)在临床型和亚临床型、肝病型和神经型间的分布差异无统计学意义。⑤纯合、错义和错义+剪接突变在临床型和亚临床型、肝病型和神经型间的分布差异无统计学意义。结论 WD患儿几乎均有肝脏受累,多以肝病表现起病。ATP7B常见突变为p.Arg778Leu、p.Pro992Leu和p.Ala874Val,常见基因型和临床表型间未发现显著相关性。p.Ala874Val/Pro突变患儿起病年龄较低,剪接突变对血清铜蓝蛋白影响较小。     

Oral zinc as initial therapy in Wilson''s disease: two years of continuous treatment in a 10-year-old child

Two years of continuous therapy promoted a significant overall amelioration in a 10-year-old boy affected by an hepatic form of Wilson's disease in which zinc sulphate was the sole therapy. In particular, liver function returned to normal and hepatic histology also improved. The parameters characterizing copper metabolism were kept under good control, and a decrease in copper concentration was found in both erythrocytes and liver. The copper balance study performed during the 25th month of treatment showed that oral zinc was still efficiently inhibiting the intestinal absorption of copper. No side effects have been reported so far.     

Mass screening for Wilson's disease: Results and recommendations

Wilson's disease is a treatable inherited disorder of copper metabolism. Established treatments include the use of oral chelating agents and the establishment of a minimum copper diet, although prognosis mainly depends on the extent of liver or nervous system damage present before treatment. Once irreversible damage has occurred, the effect of these treatments is diminished and the patient's quality of life compromised. Therefore, the establishment of a mass screening system able to detect Wilson's disease patients presymptomatically has been discussed. Recently, a monoclonal antibody specific to holoceruloplasmin has been developed. This antibody was used in a nationwide screening trial of 126,810 newborn infants, but no Wilson's disease patients were identified. However, three patients out of 24,165 were diagnosed with Wilson's disease using this specific antibody in a screening performed during the period from late infancy to elementary school. The age of 3 years is thought to be the best point for Wilson's disease mass screening. In this paper, a review of mass screening for Wilson's disease in Japan using a specific monoclonal antibody to holoceruloplasmin is presented.     

Mass screening for Wilson's disease by measuring urinary holoceruloplasmin

We conducted a mass-screening method to detect presymptomatic Wilson's disease in children by measuring urinary holoceruloplasmin.Two cases of Wilson's disease were found by testing urine samples from 48,819 children. The diagnosis was confirmed by clinical laboratory tests and the detection of a mutated ATP 7B gene.     

Acute hemolysis and liver cirrhosis as leading symptoms of Wilson's disease in childhood

Acute hemolytic anemia and the development of liver cirrhosis with ascites 3 month thereafter suggested Wilson's disease in a 12 years old child, which was confirmed by inappropriate copper metabolism. In addition, neurological symptoms and renal tubular insufficiency characterized the early stage of the disease.     

Hepatitis A super infection as a cause of liver failure in a child with Wilson's disease

Infection with hepatitis A virus can cause severe or even fatal illness in patients with chronic liver disease. Here we describe a seven-year-old girl who presented as acute liver failure and was diagnosed with Wilson's disease and later with coexistent hepatitis A infection. Wilson's disease was demonstrated on the basis of low ceruloplasmin, high urinary copper excretion, histological evidence of cirrhosis, and high biochemical estimation of liver copper concentration. Hepatitis A was diagnosed serologically. Our case suggests that acute hepatitis A may play a part in the acute decompensation seen in some cases of unrecognized Wilson's disease. We also emphasize the importance of prevention measures of hepatitis A infection in patients with chronic liver disease.     

Neonatal erythroderma as a first manifestation of Menkes disease

Menkes disease is an X-linked recessive lethal multisystemic disorder of copper metabolism. Progressive neurodegeneration, connective tissue disturbances, and peculiar kinky hair are the main manifestations. The low serum copper and ceruloplasmin suggests the diagnosis, which is confirmed by mutation analysis of the ATP7A gene. We report an exceptional presentation of classic Menkes disease with neonatal erythroderma. Genetic study revealed a deletion in exons 8 to 12 in the ATP7A gene. This study could allow pediatricians and pediatric dermatologists to diagnose the disorder as early as possible to establish prompt treatment with parenteral copper-histidine supplementation to improve prognosis.     

儿童肝豆状核变性的临床特点及基因分析(附70例报告)

目的 探讨儿童肝豆状核变性(WD)的临床特征及基因分析.方法 回顾性分析2011年1月至2021年6月中国医科大学附属盛京医院儿内科收治的70例WD患儿的临床资料.结果 70例患儿中,男性41例,女性29例,确诊时中位年龄6岁,首诊症状多数为体检时发现肝功能异常.不同临床类型表型中,肝型患儿起病年龄小、转氨酶水平高;神...     

Wilson's disease associated with pancreatitis

A 12-year-old boy presented with a 2-month history of abdominal pain and distention. A diagnosis of Wilson's disease was established, and D-penicillamine therapy was initiated. An associated pancreatitis was diagnosed on presentation, based on elevated serum amylase and an enlarged pancreas ultrasonically. Subsequently, an 18-month follow-up disclosed no abdominal pain, with repeatedly normal serum amylase level and a normal pancreas on ultrasonography. Since abdominal pain is a common symptom in Wilson's disease on presentation, this possibility should be considered in untreated patients. It is concluded that pancreatitis may be associated with Wilson's disease, possibly because of copper deposition in the pancreas, and is probably responsive to copper chelation therapy.     

Variations in the composition of breast milk in Wilson's disease

Wilson's disease is a rare genetic disorder of copper metabolism with autosomal recessive inheritance. It occurs between the 6th and 45th year of life. An early and reliable diagnosis, if possible in the preclinical stage, is the prerequisite for starting therapy in time. By the treatment the quality of life and the expectation of life are raised considerably. If consistent treatment is given, there will be no objections to pregnancy in Wilson's disease. It should be interrupted only in case of marked portal hypertension and in the presence of oesophageal varices. The examination of the breast milk of a patient suffering from Wilson's disease showed a reduction in the trace elements copper and zinc. It may be necessary to think of copper and zinc substitution in children fed with breast milk only.     

Sibling cases of a degenerative neurological disease associated with hypocupraemia and hypobetalipoproteinaemia

We describe two siblings, a boy and his younger sister, with degenerative neurological disturbances, hypocupraemia and hypobetalipoproteinaemia. The neurological features in both cases were developmental delay, dysarthria, hyperkinetics with an attention deficit, dysdiadochokinesis, night blindness, myoclonic jerks and convulsions. Their serum cooper levels did not increase despite administration of copper sulphate both orally or intravenously. The copper contents of the cultured fibroblasts in the patients were 1.5-fold that of controls.Although neurological disorders associated with abnormal copper metabolism and inherited in an X-linked manner have been previously reported, this is the first report of a neurodegenerative disease concurrent with abnormal copper metabolism and hypobetalipoproteinaemia.