Urinary copper excretion and hepatic copper concentrations in liver disease

Monitoring of Copper in Wilson Disease

(1) Introduction: Wilson's disease (WND) is an autosomal recessive disorder of copper (Cu) metabolism. Many tools are available to diagnose and monitor the clinical course of WND. Laboratory tests to determine disorders of Cu metabolism are of significant diagnostic importance. (2) Methods: A systematic review of the literature in the PubMed, Science Direct, and Wiley Online Library databases was conducted. (Results): For many years, Cu metabolism in WND was assessed with serum ceruloplasmin (CP) concentration, radioactive Cu test, total serum Cu concentration, urinary copper excretion, and Cu content in the liver. The results of these studies are not always unambiguous and easy to interpret. New methods have been developed to calculate non-CP Cu (NCC) directly. New parameters, such as relative Cu exchange (REC), reflecting the ratio of CuEXC to total serum Cu, as well as relative Cu exchange (REC), reflecting the ratio of CuEXC to total serum Cu, have been shown to be an accurate tool for the diagnosis of WND. Recently, a direct and fast LC-ICP-MS method for the study of CuEXC was presented. A new method to assess Cu metabolism during treatment with ALXN1840 (bis-choline tetrathiomolybdate [TTM]) has been developed. The assay enables the bioanalysis of CP and different types of Cu, including CP-Cu, direct NCC (dNCC), and labile bound copper (LBC) in human plasma. Conclusions: A few diagnostic and monitoring tools are available for patients with WND. While many patients are diagnosed and adequately assessed with currently available methods, diagnosis and monitoring is a real challenge in a group of patients who are stuck with borderline results, ambiguous genetic findings, and unclear clinical phenotypes. Technological progress and the characterization of new diagnostic parameters, including those related to Cu metabolism, may provide confidence in the more accurate diagnosis of WND in the future.

Neurological Wilson's Disease Signs-Hepatic Encephalopathy or Copper Toxicosis?

Wilson's disease (WD) is a rare autosomal recessive (AR) disorder resulting from mutations in the ATP7B gene, which is responsible for the encryption of transmembrane copper transporting ATPase. The symptomatic presentation of the disease is estimated to be about 1 in 30,000. The impairment of ATP7B function results in a copper overload in hepatocytes, which further leads to liver pathology. This copper overload also occurs in other organs, most particularly in the brain. This could then cause the occurrence of neurological and psychiatric disorders. Symptoms differ substantially and most often occur between the ages of 5 and 35 years. Early symptoms are commonly hepatic, neurological, or psychiatric. While disease presentation is most often asymptomatic, it could also range as far as to include fulminant hepatic failure, ataxia, and cognitive disorders. Various treatments are available for Wilson's disease, including chelation therapy and zinc salts, which can reverse copper overload through different mechanisms. In select cases, liver transplantation is recommended. New medications, such as tetrathiomolybdate salts, are currently being investigated in clinical trials. With prompt diagnosis and treatment, prognosis is favorable; however, diagnosing patients before the onset of severe symptoms is a significant concern. Early screening for WD could help in diagnosing patients earlier and improving treatment outcomes.

Wilson disease and the differential diagnosis of its hepatic manifestations: a narrative review of clinical, laboratory, and liver histological features

Objective

The goal of the present work is to provide an overview of the differential diagnosis of Wilson disease.

Background

Wilson disease is a rare condition due to copper accumulation primarily in the liver and brain. Although there is no definitive cure, current anti-copper treatments are associated with better outcomes if initiated early and if the diagnosis is made promptly. However, diagnostic delays are frequent and often Wilson disease represents a diagnostic challenge. The diagnosis ultimately relies on a combination of clinical, laboratory and genetic findings, and it is crucial that clinicians list Wilson disease in their differential diagnosis, especially in patients presenting with a hepatocellular pattern of liver injury. Some biochemical and liver histological features of Wilson disease overlap with those of more common conditions including nonalcoholic fatty liver disease, alcohol-associated liver disease, and autoimmune hepatitis. In particular, hepatic steatosis, hepatocyte glycogenated nuclei, ballooning degeneration, and Mallory-Denk bodies are often identified in Wilson disease as well as more common liver diseases. In addition, the natural history of liver damage in Wilson disease and the risk of developing liver cancer are largely understudied.

Methods

We conducted an enlarged review of published papers on Wilson disease focusing on its diagnosis and distinctive clinical and liver pathology features in relation to common non-cholestatic liver diseases with the final goal in aiding clinicians in the diagnostic process of this rare but treatable condition.

Conclusions

Aside from markedly altered copper metabolism, Wilson disease has essentially no pathognomonic features that can distinguish it from more common liver diseases. Clinicians should be aware of this challenge and consider Wilson disease in patients presenting with a hepatocellular pattern of liver injury.

Wilson's disease: Revisiting an old friend

Wilson's disease (WD) is a rare condition caused by copper accumulation primarily in the liver and secondly in other organs, such as the central nervous system. It is a hereditary autosomal recessive disease caused by a deficiency in the ATP7B transporter. This protein facilitates the incorporation of copper into ceruloplasmin. More than 800 mutations associated with WD have been described. The onset of the disease frequently includes manifestations related to the liver (as chronic liver disease or acute liver failure) and neurological symptoms, although it can sometimes be asymptomatic. Despite it being more frequent in young people, WD has been described in all life stages. Due to its fatal prognosis, WD should be suspected in all patients with unexplained biochemical liver abnormalities or neurological or psychiatric symptoms. The diagnosis is established with a combination of clinical signs and tests, including the measurement of ceruloplasmin, urinary copper excretion, copper quantification in liver biopsy, or genetic assessment. The pharmacological therapies include chelating drugs, such as D-penicillamine or trientine, and zinc salts, which are able to change the natural history of the disease, increasing the survival of these patients. In some cases of end-stage liver disease or acute liver failure, liver transplantation must be an option to increase survival. In this narrative review, we offer an overview of WD, focusing on the importance of clinical suspicion, the correct diagnosis, and treatment.

Ibuprofen-associated minimal change disease and acute interstitial nephritis with possibly linked membranous glomerulonephritis

Non-steroidal anti-inflammatory drugs are not only potent analgesics and antipyretics but also nephrotoxins, and may cause electrolyte disarray. In addition to the commonly expected effects, including hyperkalemia, hyponatremia, acute renal injury, renal cortical necrosis, and volume retention, glomerular disease with or without nephrotic syndrome or nephritis can occur as well including after years of seemingly safe administration. Minimal change disease, secondary membranous glomerulonephritis, and acute interstitial nephritis are all reported glomerular lesions seen with non-steroidal anti-inflammatory use. We report a patient who used non-steroidal anti-inflammatory drugs for years without diabetes, chronic kidney disease, or proteinuria; he then developed severe nephrotic range proteinuria with 7 g of daily urinary protein excretion. Renal biopsy showed minimal change nephropathy, a likely secondary membranous glomerulonephritis, and acute interstitial nephritis present simultaneously in one biopsy. Cessation of non-steroidal anti-inflammatory drug use along with steroid treatment resulted in a moderate improvement in renal function, though residual impairment remained. Urine heavy metal screen returned with elevated levels of urine copper, but with normal ceruloplasmin level. Workup suggested that the elevated copper levels were due to cirrhosis from non-alcoholic fatty liver disease. The membranous glomerulonephritis is possibly linked to non-steroidal anti-inflammatory drug exposure, and possibly to heavy metal exposure, and is clinically and pathologically much less likely to be a primary membranous glomerulonephritis with negative serological markers.

Biomarkers for diagnosis of Wilson's disease

BACKGROUND

Wilson's disease, first described by Samuel Wilson in 1912, is an autosomal recessive metabolic disorder resulting from mutations in the ATP7B gene. The disease develops as a consequence of copper accumulating in affected tissues. There is no gold standard for the diagnosis of Wilson's disease, which is often delayed due to the non-specific clinical features and the need for a combination of clinical and laboratory tests for diagnosis. This delay may in turn affect clinical outcome and has implications for other family members in terms of diagnosis. The Leipzig criteria were established to help standardise diagnosis and management. However, it should be emphasised that these criteria date from 2003, and many of these have not been formally evaluated; this review examines the evidence behind biochemical testing for Wilson's disease.

OBJECTIVES

To determine the diagnostic accuracy of three biochemical tests at specified cut-off levels for Wilson's disease. The index tests covered by this Cochrane Review are caeruloplasmin, 24-hour urinary copper and hepatic copper content. These tests were evaluated in those with suspected Wilson's disease and appropriate controls (either healthy or those with chronic liver disease other than Wilson's). In the absence of a gold standard for diagnosing Wilson's disease, we have used the Leipzig criteria as a clinical reference standard. To investigate whether index tests should be performed in all individuals who have been recommended for testing for Wilson's disease, or whether these tests should be limited to subgroups of individuals.

SEARCH METHODS

We identified studies by extensive searching of, e.g. the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, the Web of Science and clinical trial registries (29 May 2019). Date of the most recent search of the Cochrane Cystic Fibrosis and Genetic Disorders Inborn Errors of Metabolism Register: 29 May 2019.

SELECTION CRITERIA

We included prospective and retrospective cohort studies that assessed the diagnostic accuracy of an index test using the Leipzig criteria as a clinical reference standard for the diagnosis of Wilson's disease.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed and extracted data and assessed the methodological quality of each included study using the QUADAS-2 tool. We had planned to undertake meta-analyses of the sensitivity, specificity at relevant cut-offs for each of the biochemical tests for Wilson's, however, due to differences in the methods used for each biochemical index test, it was not possible to combine the results in meta-analyses and hence these are described narratively.

MAIN RESULTS

Eight studies, involving 5699 participants (which included 1009 diagnosed with Wilson's disease) were eligible for inclusion in the review. Three studies involved children only, one adults only and the four remaining studies involved both children and adults. Two evaluated participants with hepatic signs and six with a combination of hepatic and neurological signs and symptoms of Wilson's disease, as well as pre-symptomatic individuals. The studies were of variable methodological quality; with high risk if bias for participant selection and the reference standard used being of greatest methodological concern. Key differences between studies include differences in assay methodology, different cut-off values for diagnostic thresholds, different age and ethnicity groups. Concerns around study design imply that diagnostic accuracy figures may not transfer to populations outside of the relevant study.

INDEX TEST

caeruloplasmin Five studies evaluated various thresholds of caeruloplasmin (4281 participants, of which 541 had WD). For caeruloplasmin a cut-off of 0.2 g/L as in the Leipzig criteria achieved a sensitivity of 77.1% to 99%, with variable specificity of 55.9% to 82.8%. Using the cut-off of 0.1 g/L of the Leipzig criteria seemed to lower the sensitivity overall, 65% to 78.9%, while increasing the specificity to 96.6% to 100%.

INDEX TEST

hepatic copper Four studies evaluated various thresholds of hepatic copper (1150 participants, of which 367 had WD). The hepatic copper cut-off of 4 μmol/g used in the Leipzig criteria achieved a sensitivity of 65.7% to 94.4%, with a variable specificity of 52.2% to 98.6%.

INDEX TEST

24-hour urinary copper Three studies evaluated various thresholds of 24-hour urinary copper (268 participants, of which 101 had WD). For 24-hour urinary copper, a cut-off of 0.64 to 1.6 μmol/24 hours used in the Leipzig criteria achieved a variable sensitivity of 50.0% to 80.0%, with a specificity of 75.6% to 98.3%.

AUTHORS' CONCLUSIONS

The cut-offs used for caeruloplasmin, 24-hour urinary copper and hepatic copper for diagnosing Wilson's disease are method-dependent and require validation in the population in which such index tests are going to be used. Binary cut-offs and use of single-test strategies to rule Wilson's disease in or out is not supported by the evidence in this review. There is insufficient evidence to inform testing in specific subgroups, defined by age, ethnicity or clinical subgroups.

New tools for Wilson's disease diagnosis: exchangeable copper fraction

Wilson's disease (WD) biochemical markers continue to evolve. Classical tests [serum copper, serum ceruloplasmin (Cp), urinary copper] have their own limits, and they are often insufficient to diagnose or exclude WD. So, calculated estimation of copper that is not bound to Cp has been proposed, but it is flawed. Therefore, we focused our research on a direct measurement of serum copper labile fraction. Exchangeable copper (CuEXC) offers a correct view of the free copper overload. It provides information on the spread and severity of WD. Relative exchangeable copper (REC) (percentage of exchangeable to total serum copper) that appreciates the toxic fraction of copper in blood is an excellent biomarker for WD diagnosis. These two tests are reliable and non-invasive. They give rapid answers for an appropriate diagnosis and make possible to start the treatment quickly without waiting for the result of the genetic tests. As early diagnosis and treatment are the keystones of successful management of patients with WD, different teams have already applied these tests in a routine framework to a large number of patients.

Biochemical Markers for the Diagnosis and Monitoring of Wilson Disease

Wilson disease (WD) is an autosomal recessively-inherited disorder of copper metabolism and characterised by a pathological accumulation of copper. The ATP7B gene encodes for a transmembrane copper transporter essential for biliary copper excretion. Depending on time of diagnosis, severity of disease can vary widely. Almost all patients show evidence of progressive liver disease. Neurological impairments or psychiatric symptoms are common in WD patients not diagnosed during adolescence. WD is a treatable disorder, and early treatment can prevent the development of symptoms in patients diagnosed while still asymptomatic. This is why the early diagnosis of WD is crucial. The diagnosis is based on clinical symptoms, abnormal measures of copper metabolism and DNA analysis. Available treatment includes chelators and zinc salts which increase copper excretion and reduce copper uptake. In severe cases, liver transplantation is indicated and accomplishes a phenotypic correction of the hepatic gene defect. Recently, clinical development of the new copper modulating agent tetrathiomolybdate has started and direct genetic therapies are being tested in animal models. The following review focuses especially on biochemical markers and how they can be utilised in diagnosis and drug monitoring.

Relative exchangeable copper: A valuable tool for the diagnosis of Wilson disease

BACKGROUND & AIMS

Measuring of the relative exchangeable copper seems to be a promising tool for the diagnosis of Wilson disease. The aim of our study is to determine the performance of REC for the diagnosis of Wilson disease in a population of patients with chronic liver diseases.

METHODS

Measuring of exchangeable serum copper levels and relative exchangeable copper was performed in a group of Wilson disease patients at diagnosis or at clinical deterioration because of non-compliance (group 1, n=9), a group of stable WD patients (group 2, n=40), and two groups of patients (adult and paediatric) followed for non-Wilsonian liver diseases (group 3, n=103 and group 4, n=49 respectively).

RESULTS

Exchangeable serum copper (N: 0.6-1.1 μmol/L) was significantly higher in group 1 (mean 2.2±0.7 μmol/L) compared to the other three groups: group 2=0.9±0.4 μmol/L, group 3=1.2±0.4 μmol/L, group 4=1.1±0.3 μmol/L (P<0.05). Relative exchangeable copper was significantly higher in Wilson disease patients group 1 and 2 (mean 52.6% and 43.8%) compared to patients suffering from other liver diseases (mean 7.1% and 5.9%) (P<0.05).

CONCLUSIONS

Our study confirms that the determination of relative exchangeable copper is a highly valuable tool for the diagnosis of Wilson disease.

Diagnosis of Wilson disease

Clinical presentation of Wilson disease can vary widely; therefore diagnosis is not always straightforward. Wilson disease is not just a disease of children and young adults, but may present at any age. The key features of Wilson disease are liver disease and cirrhosis, neuropsychiatric disturbances, Kayser-Fleischer rings, and acute episodes of hemolysis, often in association with acute liver failure. Diagnosis is particularly difficult in children and in adults presenting with active liver disease. None of the available laboratory tests is perfect and may not be specific for Wilson disease. A detailed neurologic examination is required for all cases. Neuroimaging and electrophysiologic methods are helpful. To overcome the diagnostic challenge, several clinical signs (Kayser-Fleischer rings, neurologic symptoms) and laboratory features (copper in serum, urine, liver; serum ceruloplasmin; genetic testing) are scored 0 (absent) to 2 (present) and the Leipzig score is calculated. If the score is ≥4, the diagnosis of Wilson disease is very likely. For asymptomatic siblings of index patients, mutation analysis is the most reliable approach.

Other organ involvement and clinical aspects of Wilson disease

Wilson disease (WD) is a rare disorder of copper metabolism that presents mainly with hepatic and neuropsychiatric features. Copper accumulates not only in the liver and brain, but also in other organs. Liver injury can also be the cause of secondary impairment of other tissues. Therefore, the clinical manifestation of WD may be renal, cardiac, skin, osteoarticular, or endocrinologic and include other organ disturbances. Renal abnormalities include tubular dysfunction (e.g., renal tubular acidosis, aminoaciduria) and nephrolithiasis. Bone demineralization is a common manifestation in patients with WD. Cardiac injury may include arrhythmia, cardiomyopathy, and autonomic dysfunction. Different endocrine system manifestations, such as infertility or repeated miscarriages, growth and puberty disturbances, and hypoparathyroidism, are observed. Other important clinical aspects of WD include pancreas involvement, immunologic abnormalities, the presence of lipomas, and skin changes. Although other organ involvement is not common in WD and usually not severe, delayed diagnosis may lead to irreversible changes in organs and tissues. Therefore, awareness of other possible WD presentations is important in the differential diagnosis of WD.

Metal storage disorders: Wilson disease and hemochromatosis

Hereditary hemochromatosis and Wilson disease are autosomal recessive storage disorders of iron and copper overload, respectively. These metals are involved in multiple redox reactions, and their abnormal accumulation can cause significant injury in the liver and other organs. Over the last few decades clinicians have developed a much better understanding of these metals and their mechanism of action. Moreover, sophisticated molecular genetic testing techniques that make diagnostic testing less invasive are now available. This article updates and discusses the pathogenesis, diagnosis, and management of these metal storage disorders.

Comprehensive analysis on clinical features of Wilson's disease: an experience over 28 years with 133 cases

OBJECTIVES

Here, we reported our experience over 28 years with 133 cases of patients with Wilson's disease (WD) in order to illustrate the diverse clinical presentation and to improve understanding and early diagnosis of WD.

METHODS

We reviewed the medical records of patients with WD at Shengjing Hospital of China Medical University from 1993 to 2011. The clinical manifestations and laboratory findings were analyzed. The diagnosis was based on the presence of Kayser-Fleisher (K-F) rings, low serum copper levels, low serum ceruloplasmin levels, increased urinary copper concentrations before or after penicillamine challenge.

RESULTS

Among them, 93 patients mainly presented with hepatic manifestations, 27 with neural abnormalities, and 13 presented with others. Age range at diagnosis was wide (3-74 years, average 13·2 years), and five patients were over 40 years. The oldest one was aged 74 years and presented with neuropsychiatric disorder. The positive rate of K-F rings was 93·0%. The serum ceruloplasmin decreased in 83·6% patients, 24-hour urinary copper increased in 88·1% patients, and serum copper decreased in 68·9% patients. About 79·7% of patients were diagnosed within 6 months, but only 33·1% were diagnosed at their initial medical consultation. There was a substantial delay of up to 15 years.

CONCLUSIONS

The clinical manifestation of WD is very diverse and no one feature is completely reliable. Doctors in many fields have opportunities to encounter this disease, and the most important thing is to be aware of the possibility of WD.

Urinary copper elevation in a mouse model of Wilson's disease is a regulated process to specifically decrease the hepatic copper load

Body copper homeostasis is regulated by the liver, which removes excess copper via bile. In Wilson's disease (WD), this function is disrupted due to inactivation of the copper transporter ATP7B resulting in hepatic copper overload. High urinary copper is a diagnostic feature of WD linked to liver malfunction; the mechanism behind urinary copper elevation is not fully understood. Using Positron Emission Tomography-Computed Tomography (PET-CT) imaging of live Atp7b^−/− mice at different stages of disease, a longitudinal metal analysis, and characterization of copper-binding molecules, we show that urinary copper elevation is a specific regulatory process mediated by distinct molecules. PET-CT and atomic absorption spectroscopy directly demonstrate an age-dependent decrease in the capacity of Atp7b^−/− livers to accumulate copper, concomitant with an increase in urinary copper. This reciprocal relationship is specific for copper, indicating that cell necrosis is not the primary cause for the initial phase of metal elevation in the urine. Instead, the urinary copper increase is associated with the down-regulation of the copper-transporter Ctr1 in the liver and appearance of a 2 kDa Small Copper Carrier, SCC, in the urine. SCC is also elevated in the urine of the liver-specific Ctr1^−/− knockouts, which have normal ATP7B function, suggesting that SCC is a normal metabolite carrying copper in the serum. In agreement with this hypothesis, partially purified SCC-Cu competes with free copper for uptake by Ctr1. Thus, hepatic down-regulation of Ctr1 allows switching to an SCC-mediated removal of copper via kidney when liver function is impaired. These results demonstrate that the body regulates copper export through more than one mechanism; better understanding of urinary copper excretion may contribute to an improved diagnosis and monitoring of WD.

Urinary copper excretion before and after oral intake of d-penicillamine in parents of patients with Wilson's disease

BACKGROUND

Urinary copper excretion higher than 100 μg/24 h is useful for diagnosing Wilson's disease. d-Penicillamine challenge test may produce higher levels than 1400 μg/24 h, allowing for better diagnostic accuracy. This study investigated whether heterozygotes reach this value and compared copper serum levels, ceruloplasmin, and urinary copper excretion before and after administering d-penicillamine to the parents of Wilson's disease patients.

METHODS

Fifty parents of adult patients were enrolled to obtain copper serum levels and ceruloplasmin along with 24-h urinary copper excretion before and after administering 1g d-penicillamine.

RESULTS

Serum ceruloplasmin and copper levels were significantly lower in fathers than in mothers (mean 21.8×27.8 mg%; 71.4×88.0 μg%; p ≤ 0.001). The mean of basal 24-h urinary copper excretion was higher in fathers (26.2×18.7 μg/24 h, p=0.01), but did not differ between the genders after d-penicillamine (521.7×525.3, range 31.6-1085.1 μg/24h, p=0.8).

CONCLUSIONS

The mean values of serum copper, ceruloplasmin, and basal urinary copper excretion were different between males and females. The current diagnostic threshold of 24-h urinary copper excretion after d-penicillamine was not reached by heterozygotes. The increased urinary copper excretion after d-penicillamine challenge was much higher than fivefold the upper limit of normal urinary copper excretion in the majority of heterozygotes and should not be taken into account when diagnosing Wilson's disease.

EASL Clinical Practice Guidelines: Wilson's disease

This Clinical Practice Guideline (CPG) has been developed to assist physicians and other healthcare providers in the diagnosis and management of patients with Wilson's disease. The goal is to describe a number of generally accepted approaches for diagnosis, prevention, and treatment of Wilson's disease. Recommendations are based on a systematic literature review in the Medline (PubMed version), Embase (Dialog version), and the Cochrane Library databases using entries from 1966 to 2011. The Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) system used in other EASL CPGs was used and set against the somewhat different grading system used in the AASLD guidelines (Table 1A and B). Unfortunately, there is not a single randomized controlled trial conducted in Wilson's disease which has an optimal design. Thus, it is impossible to assign a high or even a moderate quality of evidence to any of the questions dealt with in these guidelines. The evaluation is mostly based on large case series which have been reported within the last decades.

Wilson's disease

In the almost 100 years since Wilson's description of the illness that now bears his name, tremendous advances have been made in our understanding of this disorder. The genetic basis for Wilson's disease - mutation within the ATP7B gene - has been identified. The pathophysiologic basis for the damage resulting from the inability to excrete copper via the biliary system with its consequent gradual accumulation, first in the liver and ultimately in the brain and other organs and tissues, is now known. This has led to the development of effective diagnostic and treatment modalities that, although they may not eliminate the disorder, do provide the means for efficient diagnosis and effective amelioration if carried out in a dedicated and persistent fashion. Nevertheless, Wilson's disease remains both a diagnostic and treatment challenge for physician and patient. Its protean clinical manifestations make diagnosis difficult. Appropriate diagnostic evaluations to confirm the diagnosis and institute treatment can be confusing. In this chapter, the clinical manifestations, diagnostic evaluation, and treatment approaches for Wilson's disease are discussed.

Clinical presentation and mutations in Danish patients with Wilson disease

This study describes the clinical presentation and diagnosis in all Danish patients (49, 41 unrelated) with Wilson disease (WND). On the basis of the number of diagnosed patients from 1990-2008, the prevalence was estimated to be 1:49 500. Among routinely used diagnostic tests, none were consistently indicative of WND, with the exception of the 24-h urine-Cu test, which is always outside the normal range. Mutations were identified in 100% of the screened ATP7B alleles (70 unrelated), including five novel mutations: p.1021K; p.G1158V; p.L1304F; IVS20-2A>G; Ex5_6del. In all, 70% of mutations were found in exons 8, 14, 17, 18, and 20. The most frequent mutation, p.H1069Q, comprised 18%. We propose a new and simple model that correlates genotype and age of onset. By assuming that the milder of two mutations is 'functionally dominant' and determines the age of onset, we classified 25/27 mutations as either severe (age of onset <20 years) or moderate (age of onset >20 years), and correctly predicted the age of onset in 37/39 patients. This method should be tested in other Wilson populations.

Usefulness of penicillamine-stimulated urinary copper excretion in the diagnosis of adult Wilson's disease

OBJECTIVE

Diagnosis of Wilson's disease (WD) is reliant on liver biopsy (LB) and measurement of hepatic copper. The aim of this study was to determine the usefulness of penicillamine-stimulated urinary copper excretion (PS-UCE), a non-invasive diagnostic test, for the diagnosis of WD in adults.

MATERIAL AND METHODS

In this prospective study of patients with suspected WD, total serum copper, ceruloplasmin, basal 24-h UCE and PS-UCE levels were measured. LB with copper determination was performed in those patients with persistent hypertransaminasemia and low ceruloplasmin or basal UCE > 40 microg/24 h. Diagnosis was established if the ceruloplasmin level was found to be < 20 mg/dl and hepatic copper > 250 microg/g. Results. A total of 115 patients were studied; LB was performed in 43, and WD was diagnosed in 6 (13.9%). Significant differences between WD and non-WD patients were found for basal UCE (WD: median 134.3 microg/24 h versus non-WD: median 19.0 microg/24 h (p < 0.05)) and PS-UCE (WD: median 1284.0 microg/24 h versus non-WD: median 776.0 microg/24 h; p < 0.01). In the ROC (receiver-operated curve) analysis, PS-UCE was the best discriminant between WD and non-WD (area under the curve (AUC) = 0.911, best cut-off point 1057 microg/24 h, 100% sensitivity, 82.3% specificity).

CONCLUSIONS

PS-UCE is probably a useful non-invasive test in the diagnosis of WD, improving the selection of patients for diagnostic liver biopsy. Patients with PS-UCE under 1057 microg/24 h only rarely will suffer from WD and are unlikely to benefit from LB.

Re-evaluation of the penicillamine challenge test in the diagnosis of Wilson's disease in children

BACKGROUNDS/AIMS

A urinary copper (Cu) >25 micromol/24 h following penicillamine had a reported specificity of 98.2% and sensitivity of 88.2% in diagnosing Wilson's disease (WD). We have re-evaluated this test. Ninety-eight subjects were studied at presentation.

METHODS

Thirty-eight (19 girls, 19 boys; median age 10.3 years; range 5-16 years) had an ultimate diagnosis of WD. Sixty (24 girls, 36 boys; median age 10.1, range 2.3-15 years) had other liver disorders. Urinary Cu was estimated for 24h before (basal Cu) and for 24h whilst giving penicillamine 500 mg orally 12 hourly x 2 (post-penicillamine Cu).

RESULTS

Both basal Cu and post-penicillamine Cu differed significantly between WD patients and controls (basal Cu: median 6.5 micromol/24 h, range 0.9-109 micromol/24 h, versus median: 0.8 micromol/24 h, range 0.1-19.5, p<0.0001; post-penicillamine Cu: median 36.9 micromol/24 h, range 1.98-219 micromol/24 h, versus median 12.35 micromol/24 h, range 0.5-49.8 micromol/24 h, p<0.0001). A post-penicillamine Cu >25 micromol/24 h was observed in 29/38 patients with WD and in 4/60 controls. 25/38 WD patients were symptomatic. Twenty-three of these and 6/13 asymptomatic siblings had a positive test. The test had a sensitivity of 76% (95% confidence interval [CI], 59.8-88.6%) and a specificity of 93% (95% CI, 83.8-98.2%). Sensitivity was better in symptomatic patients (92%, [95% CI; 74-99%]) than asymptomatic (46%, [95% CI; 19.2-74.9%]).

CONCLUSIONS

This test is valuable in the diagnosis of WD with active liver disease, but is unreliable to exclude the diagnosis in asymptomatic siblings.

Wilson disease--a practical approach to diagnosis, treatment and follow-up

Wilson disease is an inherited, autosomal recessive, copper accumulation and toxicity disorder that affects about 30 individuals per million. This rare disease is caused by mutations in the gene encoding a copper-transporting P-type ATPase, which is important for copper excretion into bile, leading to copper accumulation in the liver. Toxic copper concentrations can also be found in the brain and kidney, and clinical phenotypes include hepatic, haemolytic, neurologic and psychiatric diseases. Diagnosis is based on the combination of clinical features and findings such as increased urinary copper excretion, reduced levels of serum ceruloplasmin, high concentrations of copper in liver tissues and Kayser-Fleischer rings. Genetic studies are also becoming available for clinical use, but the utility of direct mutation analysis is limited. Wilson disease can be treated, and early diagnosis is essential: the goal of therapy is to reduce copper accumulation either by enhancing its urinary excretion or by decreasing its intestinal absorption. Medical therapies include penicillamine, trientine, zinc and tetrathiomolibdate. Liver transplantation is a relatively successful treatment option when medical therapy fails or in case of acute liver failure, even though it is also characterized by short- and long-term complications.

Wilson's disease

Progressive hepatolenticular degeneration, or Wilson's disease, is a genetic disorder of copper metabolism. Knowledge of the clinical presentations and treatment of the disease are important both to the generalist and to specialists in gastroenterology and hepatology, neurology, psychiatry, and paediatrics. Wilson's disease invariably results in severe disability and death if untreated. The diagnosis is easily overlooked but if discovered early, effective treatments are available that will prevent or reverse many manifestations of this disorder. Studies have identified the role of copper in disease pathogenesis and clinical, biochemical, and genetic markers that can be useful in diagnosis. There are several chelating agents and zinc salts for medical therapy. Liver transplantation corrects the underlying pathophysiology and can be lifesaving. The discovery of the Wilson's disease gene has opened up a new molecular diagnostic approach, and could form the basis of future gene therapy.

Wilson disease: pathophysiology, diagnosis, treatment, and screening

Wilson disease is an autosomal recessive condition of copper metabolism that was once considered fatal. The identification of the gene for Wilson disease has led to a better understanding of the molecular defect underlying this disorder and has impacted on disease diagnosis for some individuals. Medical therapy with chelating agents or zinc salts remains the mainstay of therapy for most patients, and liver transplant is lifesaving for those with advanced disease refractory to medical therapy or with fulminant hepatic failure. Future cell-based and genetic therapies may provide a cure for this disorder.

Effect of Silica Exposure on Urinary Excretion of Copper and Zinc

BACKGROUND

Occupational exposure to silica could lead to renal histological alterations in the glomeruli and proximal tubules. We investigated urinary excretion of copper and zinc and its possible relationship to renal alterations and work duration among nonsmoking, silica-exposed workers.

METHODS

Thirty-six control subjects (age, 39.08 +/- 6.65 years) and 48 silica-exposed workers (age, 36.79 +/- 7.33 years) were included in the present study. The exposed workers were grouped into workers with <10 years' work duration (n = 9; age, 29.0 +/- 1.50 years) and workers with > or =10 years' work duration (n = 39; age, 38.59 +/- 6.94 years). Glomerular function was assessed by measuring urinary level of microalbumin, and proximal tubular reabsorption function was assessed by measuring urinary level of alpha1-microglobulin. Structural integrity of proximal tubules was studied by measuring urinary activity of cytosolic enzyme glutathione S-transferase (GST). Also, urinary levels of copper, zinc, and creatinine were measured.

RESULTS

All measured urinary parameters were significantly increased among silica-exposed workers compared with control subjects. A significant correlation was observed between urinary levels of each of copper and zinc with the glomerular and proximal tubular functional and structural urinary parameters as well as work duration.

CONCLUSIONS

Occupational silica exposure may lead to increased urinary loss of copper and zinc as protein-metal complex, and the urinary level of these essential trace elements may be a marker for renal dysfunction. The urinary excretion of GST may be a useful marker for proximal tubular injury.

Diagnosis and treatment of Wilson's disease

Wilson's disease (WD) is an autosomal recessive disease that causes increased copper deposition in the liver and basal ganglia with resultant hepatic and neurologic sequelae. In the past few years, dramatic new discoveries have changed our understanding of the pathophysiology of WD. Although there are potentially life-saving therapies for WD, there is much controversy surrounding the optimal treatments of patients in the various stages of the disease. Specifically, the relative roles of penicillamine, trientene, and tetrathiomolybdate in the initial treatment of the symptomatic patient with WD remain to be defined. Zinc monotherapy for maintenance treatment and in the treatment of asymptomatic patients with WD is still controversial. It is also unclear whether neurologic status alone is an indication for liver transplantation in WD. This paper reviews the pathogenesis, genetics, clinical presentation, and diagnosis, with a special emphasis on the treatment controversies that arise in the care of the WD patient.

A high index of suspicion: the key to an early diagnosis of Wilson's disease in childhood

BACKGROUND

To study the clinical features of Wilson's disease in childhood.

METHODS

Retrospective review of the clinical, laboratory, and histologic features and prognosis of Wilson's disease in 26 Spanish children.

RESULTS

The first medical visit, at age 9.8+/-3.4 years (range, 4-16 years), was prompted by liver dysfunction detected accidentally (61%), symptoms of liver disease (27%), family screening (8%), and extrapyramidal symptoms and personality changes (4%). There were laboratory data of hepatic failure in 27%. All copper metabolism test results (total serum copper, 24-hour urine excretion, serum ceruloplasmin) were abnormal in 62%, two in 27%, and one in 11%. All patients in whom extrahepatic involvement was found at diagnosis had severe liver disease. Histologic findings were portal fibrosis with steatosis (29%), cirrhosis (21%), portal fibrosis (17%), chronic active hepatitis (17%), and minimal changes or normality (17%). Penicillamine was administered to all but one patient. Four children underwent liver transplantation, three of them having received penicillamine for 12, 45, and 70 days. Three other patients recovered from liver failure after 1 year of treatment with penicillamine. After a follow-up of 4.5+/-3.3 years, all the children survived. Penicillamine caused severe toxicity in one patient.

CONCLUSIONS

Wilson's disease in childhood is generally detected by maintaining a high suspicion of liver disease in patients who have no or nonspecific hepatic symptoms. Kayser-Fleischer ring is rare in childhood. Drug therapy is effective and well tolerated, even in some cases of hepatic insufficiency.

Wilson's disease. Update of a systemic disorder with protean manifestations

In Wilson's disease, a genetic defect in a copper transporter causes defective incorporation of copper into apo-ceruloplasmin and the failure to excrete copper into bile. Copper accumulated in hepatocytes generates damage via reactive oxygen species. Release of copper from necrotic hepatocytes leads to damage of other tissues, including the brain, urinary tract, red blood cells, heart, endocrine glands, skin, pancreas, bones, and joints. Treatment is designed to chelate the excess copper for urinary excretion, prevent copper absorption, and render tissue copper nontoxic. Liver transplantation, with replacement of the defective hepatic gene, may be necessary in some cases.

Wilson's disease: current status

OBJECTIVE

To review current concepts about the pathogenesis, clinical manifestations, and treatment of Wilson's disease, with an emphasis on recent developments.

DATA IDENTIFICATION

Published information was identified using MEDLINE and through extensive manual searching of bibliographies in identified sources.

RESULTS

The basic biochemical alteration responsible for deranged hepatobiliary copper homeostasis in Wilson's disease has yet to be identified. The gene for Wilson's disease has been mapped to chromosome 13, but the function of its gene product has not yet been determined. The clinical manifestations of Wilson's disease are varied and often nonspecific and include a range of hepatic, neurologic, and psychiatric findings. Penicillamine remains the drug of choice for the treatment of Wilson's disease, but recent experience suggests that trientine and zinc may be safe, effective alternatives. All three drugs are probably safe for use in pregnant patients with Wilson's disease. Liver transplantation is the only effective treatment for Wilsonian fulminant hepatic failure and corrects the underlying metabolic defect.

CONCLUSIONS

Wilson's disease is a disorder of hepatobiliary copper excretion manifested predominantly by hepatic and neurologic copper toxicosis and inherited in an autosomal recessive pattern. Although the specific underlying biochemical defect remains to be defined, specific therapy is available and usually successful. Maintaining a high index of suspicion is critical in diagnosing this readily treatable inherited disease.

Abnormalities in tests of copper metabolism in primary sclerosing cholangitis

Primary sclerosing cholangitis is a chronic, cholestatic syndrome characterized by fibrosing inflammation of the bile ducts that may lead to cirrhosis and death from liver failure. Previous reports have suggested abnormal hepatic copper metabolism in this disease. Therefore, in 70 patients, we prospectively determined the levels of hepatic copper, serum copper, and serum ceruloplasmin, and the rate of urinary copper excretion to assess the diagnostic and prognostic usefulness of these tests. Virtually all patients had at least one abnormal copper test. Hepatic copper levels were elevated in 87% of patients [292 +/- 38 micrograms/g dry wt (mean +/- SE)] and 24-h urinary copper levels in 64% of patients [135 +/- 15 micrograms/24 h (mean +/- SE)] to values comparable to those seen in Wilson's disease or primary biliary cirrhosis. In advanced histologic stages of primary sclerosing cholangitis, progressively higher mean levels of hepatic and urinary copper were found. In the liver, mean copper content (in micrograms per gram dry weight) in disease stages I and II was 147 +/- 36 (mean +/- SE); in stage III (fibrosis), 302 +/- 68; and in stage IV (cirrhosis), 379 +/- 69. In the urine, mean copper excretion (in micrograms per 24 h) in stages I and II was 72 +/- 14 (mean +/- SE); in stage III, 100 +/- 14; and in stage IV, 207 +/- 30. Higher hepatic and urinary copper levels at initial evaluation were associated with decreased survival during a median follow-up period of 2.6 yr: patients with hepatic copper greater than 250 micrograms/g dry wt and urinary copper excretion greater than 200 micrograms/24 h at initial evaluation had an 18-mo survival of less than 60%. We conclude that abnormal copper metabolism is a universal feature of primary sclerosing cholangitis, that hepatic copper accumulates and urinary copper excretion increases as the disease progresses, and that the hepatic copper concentration and the 24-h urinary copper determination are useful prognostic indicators in this disease.