Exchangeable copper: a reflection of the neurological severity in Wilson's disease

Determination of copper status by five biomarkers in serum of healthy women

BACKGROUND

The essential trace element copper is relevant for many important physiological processes. Changes in copper homeostasis can result from disease and affect human health. A reliable assessment of copper status by suitable biomarkers may enable fast detection of subtle changes in copper metabolism. To this end, additional biomarkers besides serum copper and ceruloplasmin (CP) concentrations are required.

OBJECTIVES

The aim of this study was to investigate the emerging copper biomarkers CP oxidase (CPO) activity, exchangeable copper (CuEXC) and labile copper in serum of healthy women and compare them with the conventional biomarkers total serum copper and CP.

METHOD AND MAIN FINDINGS

This observational study determined CPO activity, the non CP-bound copper species CuEXC and labile copper, total serum copper and CP in sera of 110 healthy women. Samples were collected at four time points over a period of 24 weeks. The concentrations of total serum copper and CP were within the reference ranges. The comparison of all five biomarkers provided insight into their relationship, the intra- and inter-individual variability as well as the age dependence. The correlation and Principal Component Analyses (PCA) indicated that CP, CPO activity and total copper correlated well, followed by CuEXC, while the labile copper pool was unrelated to the other parameters.

CONCLUSIONS

This study suggests that the non-CP-bound copper species represent copper pools that are differently regulated from total copper or CP-bound copper, making them interesting complementary biomarkers to enable a more complete assessment of body copper status with potential relevance for clinical application.

Distribution of non-ceruloplasmin-bound copper after i.v. 64Cu injection studied with PET/CT in patients with Wilson disease

Background & Aims

In Wilson disease (WD), copper accumulation and increased non-ceruloplasmin-bound copper in plasma lead to liver and brain pathology. To better understand the fate of non-ceruloplasmin-bound copper, we used PET/CT to examine the whole-body distribution of intravenously injected 64-copper (64Cu).

Methods

Eight patients with WD, five heterozygotes, and nine healthy controls were examined by dynamic PET/CT for 90 min and static PET/CT up to 20 h after injection. We measured 64Cu activity in blood and tissue and quantified the kinetics by compartmental analysis.

Results

Initially, a large fraction of injected 64Cu was distributed to extrahepatic tissues, especially skeletal muscle. Thus, across groups, extrahepatic tissues accounted for 45-58% of the injected dose (%ID) after 10 min, and 45-55% after 1 h. Kinetic analysis showed rapid exchange of 64Cu between blood and muscle as well as adipose tissue, with 64Cu retention in a secondary compartment, possibly mitochondria. This way, muscle and adipose tissue may protect the brain from spikes in non-ceruloplasmin-bound copper. Tiny amounts of cerebral 64Cu were detected (0.2%ID after 90 min and 0.3%ID after 6 h), suggesting tight control of cerebral copper in accordance with a cerebral clearance that is 2-3-fold lower than in muscle. Compared to controls, patients with WD accumulated more hepatic copper 6-20 h after injection, and also renal copper at 6 h.

Conclusion

Non-ceruloplasmin-bound copper is initially distributed into a number of tissues before being redistributed slowly to the eliminating organ, the liver. Cerebral uptake of copper is extremely slow and likely highly regulated. Our findings provide new insights into the mechanisms of copper control.

Impact and implications

Maintaining non-ceruloplasmin-bound copper within the normal range is an important treatment goal in WD as this "free" copper is considered toxic to the liver and brain. We found that intravenously injected non-ceruloplasmin-bound copper quickly distributed to a number of tissues, especially skeletal muscle, subcutaneous fat, and the liver, while uptake into the brain was slow. This study offers new insights into the mechanisms of copper control, which may encourage further research into potential new treatment targets.

Clinical trial number

2016-001975-59.

Challenges and dilemmas in pediatric hepatic Wilson's disease

Wilson disease is an autosomal recessive disorder affecting the ATP7B gene located on chromosome 13q. This leads to copper deposition in various organs, most importantly in the liver and brain. The genetic mutations are vast, well reported in the West but poorly documented in developing countries. Hence the diagnosis is made with a constellation of clinico-laboratory parameters which have significant overlap with other liver diseases and often pose a significant dilemma for clinicians. Diagnostic scoring systems are not fool-proof. The availability and affordability of chelators in developing countries impact the drug compliance of patients. While D-penicillamine is a potent drug, its side effects lead to drug discontinuation. Trientine is cost-prohibitive in developing countries. There is no single test to assess the adequacy of chelation. Exchangeable urinary copper is an essential upcoming diagnostic and prognostic tool. In the presence of cirrhosis, hypersplenism clouds the assessment of myelosuppression of drugs. Similarly, it may be difficult to distinguish disease tubulopathy from drug-induced glomerulonephritis. Neurological worsening due to chelators may appear similar to disease progression. Presentation as fulminant hepatic failure requires rapid workup. There is a limited window of opportunity to salvage these patients with the help of plasmapheresis and other liver-assisted devices. This review addresses the challenges and clinical dilemmas faced at beside in developing countries.

Can Patients with Wilson's Disease Develop Copper Deficiency?

Background

Wilson's disease (WD) is a rare genetic condition characterized by a copper overload in organs secondary to mutation in ATP7B gene. Lifelong decoppering treatments are the keystone of the treatment but must be regularly adapted to obtain a correct copper balance and could lead to copper deficiency (CD).

Objectives

Study the characteristics of CD in WD patients.

Methods

CD cases from our cohort of 338 WD patients have been investigated. CD was defined by the association of serum copper, exchangeable copper and urinary copper excretion assays less than two standard deviations from the mean with cytopenia and/or neurological damage of spinal cord origin. A systematic review of literature about cases of CD in WD patient was performed in PubMed database according to PRISMA guidelines.

Results

Three WD patients were diagnosed with CD in our cohort. Review of the literature found 17 other patients. Most of the patients had anemia and neutropenia associated with neurological symptoms (especially progressive posterior cord syndrome). All the patients were treated with Zinc salts and the symptoms occurred more than a decade after the initiation of treatment. The adaptation of the treatment allowed a correction of the cytopenia but only a partial improvement of the neurological symptoms.

Conclusions

WD patients can develop CD after many years of zinc therapy. Anemia and neutropenia are red flags that should evoke CD.

Benefits of using exchangeable copper and the ratio of exchangeable copper in a real-world cohort of patients with Wilson disease

Wilson disease (WD) is a complex disease in which diagnosis and long-term metabolic copper control remains challenging. The absence of accurate biomarkers requires the combination of different parameters to ensure copper homeostasis. Exchangeable copper and its ratio (REC) have been suggested to be useful biomarkers in this setting. We aimed at introducing these measurements and evaluate their performance and accuracy in our real-world cohort of WD patients. Exchangeable copper and REC were measured in 48 WD patients and 56 control individuals by inductively coupled plasma-mass-spectrometry. Demographic and clinical characteristics were collected. REC was shown to be significantly higher among WD patients compared to controls and useful for WD identification by using the previously established cutoffs: 71.4% of WD patients with a recent diagnosis had REC ≥18.5% and 95.1% of long-term treated WD had REC ≥14%; only four patients of the cohort presented discordant levels. Moreover, REC values were below 15% in all the control individuals. Exchangeable copper was significantly higher in WD patients compared to controls and tended to be reduced among WD patients who were compliant to medication. This real-life study confirmed that exchangeable copper and REC are useful serum biomarkers that can be used as complementary tests to ensure WD diagnosis (REC) and copper homeostasis whithin time (exchangeable copper). The desirable target levels for this last objective still needs to be validated in prospective cohorts.

D-Penicillamine-Induced Myasthenia Gravis-A Probable Complication of Wilson's Disease Treatment-A Case Report and Systematic Review of the Literature

Wilson's disease (WD) is a genetic disorder with copper accumulation in various tissues leading to related clinical symptoms (mainly hepatic and neuropsychiatric) which can be in 85% of patients successfully treated with anti-copper agents. However, during WD treatment neurological deterioration may occur in several patients. D-penicillamine (DPA) is one of the most frequently used drugs in WD treatment. Despite its efficacy, DPA can produce many adverse drug reactions, which should be recognized early. We present the case of a 51-year-old man diagnosed with the hepatic form of WD and initially treated with DPA in whom after 15 months of treatment, diplopia and evening ptosis occurred. WD treatment non-compliance as well as overtreatment were excluded. Supported by neurological symptoms, a positive edrophonium test, and high serum levels of antibodies against acetylcholine receptors (AChR-Abs), as well as low concentrations of antibodies against muscle-specific kinase (MuSK-Abs), the diagnosis of myasthenia gravis (MG), induced by DPA, was established. DPA was stopped; zinc sulfate for WD and pyridostigmine for MG symptoms were introduced. Diplopia and ptosis subsided after a few days, which supported our diagnosis. During a follow-up visit after 6 months, the patient did not present any MG symptoms. AChR-Abs level gradually decreased and MuSK-Abs were no longer detected. Pyridostigmine was stopped, and within 9 months of follow-up, the neurological symptoms of MG did not reoccur. The authors discussed the patient's neurological deterioration, performed a systematic review of DPA-induced MG in WD and concluded that MG is a rare and usually reversible complication of DPA treatment. DPA-induced MG generally occurs 2-12 months after treatment initiation and ocular symptoms predominate. Response to pyridostigmine treatment is good and MG symptoms usually reverse within one year after DPA treatment cessation. However, symptoms may persist in some cases where DPA treatment is only a trigger factor for MG occurrence.

A fluorometric assay to determine labile copper(II) ions in serum

Labile copper(II) ions (Cu2+) in serum are considered to be readily available for cellular uptake and to constitute the biologically active Cu2+ species in the blood. It might also be suitable to reflect copper dyshomeostasis during diseases such as Wilson's disease (WD) or neurological disorders. So far, no direct quantification method has been described to determine this small Cu2+ subset. This study introduces a fluorometric high throughput assay using the novel Cu2+ binding fluoresceine-peptide sensor FP4 (Kd of the Cu2+-FP4-complex 0.38 pM) to determine labile Cu2+ in human and rat serum. Using 96 human serum samples, labile Cu2+was measured to be 0.14 ± 0.05 pM, showing no correlation with age or other serum trace elements. No sex-specific differences in labile Cu2+ concentrations were noted, in contrast to the total copper levels in serum. Analysis of the effect of drug therapy on labile Cu2+ in the sera of 19 patients with WD showed a significant decrease in labile Cu2+ following copper chelation therapy, suggesting that labile Cu2+ may be a specific marker of disease status and that the assay could be suitable for monitoring treatment progress.

Neurological worsening in Wilson disease - clinical classification and outcome

BACKGROUND & AIMS

Prevention of neurological worsening (NW) under therapy is an unmet need in the management of Wilson disease (WD). In this study, we aimed to characterize the occurrence, associated outcomes and potential reversibility of NW in WD.

METHODS

From a total cohort of 457 patients with WD, 128 patients with WD and neurological features at any time point (all Caucasian, 63 females, median age at diagnosis 22 years) were identified by chart review at University Hospital Heidelberg and grouped according to initial presentation. The timing and occurrence of NW was assessed following a structured clinical examination during clinical visits.

RESULTS

Early NW (within the first 3 months of therapy) was observed in 30 out of 115 (26.1%) patients with neurological or mixed presentation and never in patients with a purely hepatic or asymptomatic presentation (0%). Late NW (after >12 months) was seen in a further 23 (20%) with neurological or mixed presentation and in 13 out of 294 (4.4%) patients with a hepatic or asymptomatic presentation. The median time from start of treatment to late NW was 20 months. Only three patients experienced NW between 3 and 12 months. NW was observed with D-penicillamine, trientine and zinc therapy and was reversible in 15/30 (50%) with early NW and in 29/36 (81%) with late NW.

CONCLUSIONS

In this study, we identified two peaks in NW: an early (≤3 months) treatment-associated peak and a late (>12 months of treatment) adherence-associated peak. Early paradoxical NW was attributed to treatment initiation and pre-existing neurological damage, and was not observed in those with a hepatic or asymptomatic presentation. Late NW is likely to be associated with non-adherence.

IMPACT AND IMPLICATIONS

In patients with Wilson disease, defined as an excess accumulation of copper which can damage the liver, brain and other vital organs, neurological worsening can occur despite chelation therapy. The study identifies different patterns of 'early' (<3 months) vs. 'late' (>12 months) neurological worsening in relation to initiation of chelation therapy and establishes possible causes and the potential for reversibility. These data should be useful for counseling patients and for guiding the optimal management of chelation therapy.

ARBM101 (Methanobactin SB2) Drains Excess Liver Copper via Biliary Excretion in Wilson's Disease Rats

BACKGROUND & AIMS

Excess copper causes hepatocyte death in hereditary Wilson's disease (WD). Current WD treatments by copper-binding chelators may gradually reduce copper overload; they fail, however, to bring hepatic copper close to normal physiological levels. Consequently, lifelong daily dose regimens are required to hinder disease progression. This may result in severe issues due to nonadherence or unwanted adverse drug reactions and also due to drug switching and ultimate treatment failures. This study comparatively tested bacteria-derived copper binding agents-methanobactins (MBs)-for efficient liver copper depletion in WD rats as well as their safety and effect duration.

METHODS

Copper chelators were tested in vitro and in vivo in WD rats. Metabolic cage housing allowed the accurate assessment of animal copper balances and long-term experiments related to the determination of minimal treatment phases.

RESULTS

We found that copper-binding ARBM101 (previously known as MB-SB2) depletes WD rat liver copper dose dependently via fecal excretion down to normal physiological levels within 8 days, superseding the need for continuous treatment. Consequently, we developed a new treatment consisting of repetitive cycles, each of ∼1 week of ARBM101 applications, followed by months of in-between treatment pauses to ensure a healthy long-term survival in WD rats.

CONCLUSIONS

ARBM101 safely and efficiently depletes excess liver copper from WD rats, thus allowing for short treatment periods as well as prolonged in-between rest periods.

Copper homeostasis dysregulation promoting cell damage and the association with liver diseases

ABSTRACT

Copper plays an important role in many metabolic activities in the human body. Copper level in the human body is in a state of dynamic equilibrium. Recent research on copper metabolism has revealed that copper dyshomeostasis can cause cell damage and induce or aggravate some diseases by affecting oxidative stress, proteasome, cuprotosis, and angiogenesis. The liver plays a central role in copper metabolism in the human body. Research conducted in recent years has unraveled the relationship between copper homeostasis and liver diseases. In this paper, we review the available evidence of the mechanism by which copper dyshomeostasis promotes cell damage and the development of liver diseases, and identify the future research priorities.

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.

Blood Based Biomarkers of Central Nervous System Involvement in Wilson's Disease

Wilson's disease (WD) is an inherited disorder of copper metabolism with clinical symptoms related to pathological copper accumulation, which are mainly hepatic and/or neuropsychiatric. The disease is potentially treatable with pharmacological agents (chelators or zinc salts). As such, key factors for a favorable treatment outcome are early diagnosis and anti-copper treatment initiation as well as appropriate treatment monitoring for safety and efficacy. Despite the generally favorable outcome in most treated patients, almost 10% of the general population of WD patients and about 25% of patients in the group with initial neurological phenotype of disease experience early neurological deterioration. In almost 50% of patients with neurological symptoms, the symptoms persist. A search for new treatment modalities (e.g., gene therapy, molybdenum salts) aims to prevent early neurological deterioration as well as improve treatment outcomes. In addition to evaluating the clinical signs and symptoms of the disease, serum biomarkers for diagnosis and treatment monitoring are very important for WD management. Sensitive serum biomarkers of copper metabolism and liver injury are well described. However, there is a need to establish blood-based biomarkers of central nervous system (CNS) injury to help identify patients at risk of early neurological deterioration and aid in their monitoring. Based on the available literature and studies of WD patients, the authors reviewed serum biomarkers of CNS involvement in WD, as well as their potential clinical significance.

Challenges in pediatric inherited/metabolic liver disease: Focus on the disease spectrum, diagnosis and management of relatively common disorders

The clinical scenario of pediatric liver disease is becoming more intricate due to changes in the disease spectrum, in which an increasing number of inherited/ metabolic liver diseases are reported, while infectious diseases show a decreasing trend. The similar clinical manifestations caused by inherited/metabolic diseases might be under-recognized or misdiagnosed due to nonspecific characteristics. A delayed visit to a doctor due to a lack of symptoms or mild symptoms at an early stage will result in late diagnosis and treatment. Moreover, limited diagnostic approaches, especially liver biopsy, are not easily accepted by pediatric patients, leading to challenges in etiological diagnosis. Liver dysfunction due to inherited/metabolic diseases is often caused by a variety of metabolites, so precision treatment is difficult; symptomatic treatment is a compelling option for inherited disorders.

Wilson's disease: best practice

Wilson's disease is an autosomal recessive disorder arising from pathogenic variants in the Atp7b gene on chromosome 13. The defective translated ATPase copper (Cu) transport protein produced leads to Cu accumulation, initially affecting the liver but eventually affecting other cells. It is just over 20 years since the last Best Practice on this topic in this journal. This review is an update on this, covering new disease biomarkers, pathogenesis, assumptions around clinical features and developments in therapy.

Diagnosis and Outcomes of Late-Onset Wilson's Disease: A National Registry-Based Study

BACKGROUND

Wilson's disease (WD) is usually diagnosed in children and young adults; limited data exist on late-onset forms.

OBJECTIVE

The aim was to characterize the clinical and paraclinical presentations, therapeutic management, and outcomes in patients with late-onset WD.

METHODS

Patients diagnosed with WD after age 40 years were identified from the French Wilson's Disease Registry (FWDR). Clinical, laboratory, and imaging findings and treatment were reported at diagnosis and last follow-up.

RESULTS

Forty-five patients were identified (median age: 49, range: 40-64) and placed in three groups according to their clinical presentation: neurological (n = 20, median diagnostic delay: 20 months), hepatic (n = 13, diagnostic delay: 12 months), and family screening (n = 12), all confirmed genetically. Six neurological patients had an atypical presentation (1 torticollis, 2 writer's cramps, 2 functional movement disorders, and 1 isolated dysarthria), without T2/fluid-attenuated inversion recovery brain magnetic resonance imaging (MRI) hyperintensities; 5 of 6 had no Kayser-Fleischer ring (KFR); 5 of 6 had liver involvement. In the neurological group, 84% of patients improved clinically, and 1 developed copper deficiency. In the hepatic group, 77% had cirrhosis; 6 patients required liver transplantation. In the screened group, 43% had mild liver involvement; 3 were not treated and remained stable; 24-h urinary copper excretion was normal in 33% of patients at diagnosis.

CONCLUSIONS

In the FWDR, late-onset forms of WD affect 8% of patients, mostly with neurological presentations. Thirty percent of the neurological forms were atypical (isolated long-lasting symptoms, inconspicuous brain MRI, no KFR). With personalized treatment, prognosis was good. This study emphasized that WD should be suspected at any age and even in cases of atypical presentation. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Wilson Disease and Alpha1-Antitrypsin Deficiency: A Review of Non-Invasive Diagnostic Tests

Wilson disease and alpha1-antitrypsin deficiency are two rare genetic diseases that may impact predominantly the liver and/or the brain, and the liver and/or the lung, respectively. The early diagnosis of these diseases is important in order to initiate a specific treatment, when available, ideally before irreversible organ damage, but also to initiate family screening. This review focuses on the non-invasive diagnostic tests available for clinicians in both diseases. These tests are crucial at diagnosis to reduce the potential diagnostic delay and assess organ involvement. They also play a pivotal role during follow-up to monitor disease progression and evaluate treatment efficacy of current or emerging therapies.

Trientine tetrahydrochloride versus penicillamine for maintenance therapy in Wilson disease (CHELATE): a randomised, open-label, non-inferiority, phase 3 trial

BACKGROUND

Wilson disease is an inherited disorder of copper transport. Whereas penicillamine is used therapeutically to re-establish copper balance, trientine is indicated for patients with penicillamine intolerance. We aimed to compare penicillamine with trientine tetrahydrochloride (TETA4) for maintenance therapy in patients with Wilson disease.

METHODS

We conducted a randomised, open-label, non-inferiority, phase 3 trial at 15 health-care centres across nine countries (patients were recruited from 13 of these health-care centres across Brazil, Europe, and the USA). We enrolled patients aged 18-75 years with stable Wilson disease who were treated for at least 1 year with penicillamine. Patients entered a 12-week period to determine stability through clinical assessment by site investigators and predefined thresholds for serum non-caeruloplasmin-bound copper (NCC; by an exchangeable copper assay; 25-150 μg/L), 24 h urinary copper excretion (100-900 μg/24 h), and alanine aminotransferase (ALT; <2 × upper limit of normal). Stable patients were randomly assigned (1:1) to continue receiving the maintenance twice daily dose of oral penicillamine or switched mg-for-mg to oral TETA4 centrally with a web-based system using minimisation. The primary endpoint, assessed 24 weeks after randomisation, was NCC by speciation assay. The non-inferiority margin of mean difference in NCC by speciation assay was -50 μg/L, as estimated by a general linear model for repeated visits, adjusted for baseline values. Further data on safety and efficacy were collected during a 24-week extension period. Data were analysed using an intention-to-treat approach. Safety was assessed in all patients who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT03539952 (active, not recruiting).

FINDINGS

Between June 4, 2018, and March 10, 2020, 77 patients were screened. 53 patients were randomly assigned (27 to the penicillamine group and 26 to the TETA4 group). After 24 weeks, the mean difference in serum NCC by speciation assay between the penicillamine group and TETA4 group was -9·1 μg/L (95% CI -24·2 to 6·1), with the lower limit of the 95% CI within the defined non-inferiority margin. At 24 weeks, urinary copper excretion was lower with TETA4 than with penicillamine (mean difference 237·5 μg/24 h (99% CI 115·6 to 359·4). At 48 weeks, TETA4 remained non-inferior to penicillamine in terms of NCC by speciation assay (mean difference NCC -15·5 μg/L [95% CI -34·5 to 3·6]). Urinary copper excretion at 48 weeks remained in the expected range for well treated patients in both study groups, and the mean difference (124·8 μg/24 h [99% CI -37·6 to 287·1]) was not significantly different. At 24 weeks and 48 weeks, masked clinical adjudication of stability assessed by three independent clinicians confirmed clinical stability (100%) of all participants, in agreement with the stability seen with the NCC by speciation assay. There were no notable changes in either the Clinical Global Impression of Change or Unified Wilson Disease Rating Scale (neurological assessment) from baseline (pre-randomisation) at weeks 24 and 48. The mean change in serum total copper from baseline to 24 weeks was 17·6 μg/L (99% CI -9·5 to 44·7) with penicillamine and -6·3 μg/L (-34·7 to 22·1) with TETA4, and the mean change in serum total caeruloplasmin from baseline to 24 weeks was 1·8 mg/L (-19·2 to 22·8) with penicillamine and -2·2 mg/L (-6·1 to 1·7) with TETA4. All liver enzymes were similar at 24 weeks and 48 weeks, with the exception of elevated ALT concentration at 48 weeks for patients in the TETA4 group. Penicillamine was associated with three post-randomisation serious adverse events (leukopenia, cholangiocarcinoma, and hepatocellular cancer); none were reported for TETA4. The most common treatment-emergent adverse events were headache for penicillamine (five [19%] of 27 patients vs two [8%] of 26) and abdominal pain for TETA4 (one [4%] vs four [15%]); all treatment-emergent adverse events resolved and were mild to moderate. One patient developed a rash with TETA4 that resolved on discontinuation of therapy.

INTERPRETATION

The efficacy of TETA4 as oral maintenance therapy was non-inferior to penicillamine and well tolerated in adults with Wilson disease.

FUNDING

Orphalan.

Maintenance therapy simplification using a single daily dose: A preliminary real-life feasibility study in patients with Wilson disease

BACKGROUND

Single daily dose (SDD) is a good way to improve adherence by simplifying treatment. Efficacy data concerning patients with Wilson disease (WD) taking an SDD are lacking.

AIM

To report the effectiveness of the use of SDD for the treatment of WD.

METHODS

This retrospective study included WD patients followed in the French National Network who received an SDD in maintenance phase. The treatment failure was defined as a composite criterion with the occurrence of at least one of the following criterion: death, transplantation, increase of transaminases >2xULN, hepatic decompensation, neurological aggravation, severe side effects related to treatment, and/or discontinuation of treatment.

RESULTS

A total of 26 patients received an SDD (D-penicillamine=13, trientine=8, zinc=5) after a median interval of 152 months after diagnosis. After one year, two patients had treatment failure: transaminitis in one, continuation of neurological deterioration in the other related to a poor compliance. After a median duration of 41 months on SDD, 3 other patients had treatment failure (transaminitis=2, treatment discontinuation=1). There was no death, no liver transplantation, no hepatic decompensation, and no severe side effects related to treatment during the follow-up. Moreover, transaminases and serum exchangeable copper were not significantly different 1 year post-switch and at last follow-up compared to baseline.

CONCLUSIONS

Maintenance therapy simplification through the use of an SDD could be considered in some WD patients. In this pilot study, SDD was effective in 21/26 patients (81%) without any concern regarding safety.

Long-Term Urinary Copper Excretion and Exchangeable Copper in Children With Wilson Disease Under Chelation Therapy

OBJECTIVES

Determining 24-hour urinary copper excretion (UCE) levels is useful for diagnosing Wilson's disease (WD) and for treatment monitoring. Exchangeable copper (ExC) is a novel potential marker, but its long-term changes have never been described in patients under chelation therapy. Our aim was to describe the long-term changes in ExC levels compared to UCE levels in symptomatic WD pediatric patients under chelation therapy.

METHODS

A retrospective, descriptive, and analytical study including all patients under 18 years of age, diagnosed between 2006 and 2020, and treated with chelation therapy was conducted at the National Reference Center for WD in Lyon. Ceruloplasmin levels, serum copper, 24 h-UCE, ExC, and liver enzymes at diagnosis and during follow-up were analyzed.

RESULTS

Our study included 36 patients, predominantly with hepatic form of WD (n = 31). The median [interquartile range (IQR)] age at diagnosis was 10.5 (8.4-13.1) years, and the median (IQR) follow-up duration was 6.3 (3.3-8.8) years. At diagnosis, the median (IQR) ExC value was 1.01 (0.60-1.52) µmol/L. There was a significant decrease during the first year of chelation treatment ( P = 0.0008), then a stabilization. The median (IQR) ExC values was 0.38 (0.22-0.63) µmol/L at 12-18 months and 0.43 (0.31-0.54) µmol/L at 5 years of chelation treatment ( P = 0.4057). Similarly, there was a significant decrease in 24-hour UCE ( P &lt; 0.001) during the first year of chelation treatment, then a stabilization.

CONCLUSIONS

Our study showed a significant decrease in ExC and 24-hour UCE levels during the first year of follow-up; The dynamics of both biomarkers were similar along the follow-up, demonstrating their usefulness in clinical practice for monitoring WD.

The Role of Zinc in the Treatment of Wilson’s Disease

Wilson’s disease (WD) is a hereditary disorder of copper metabolism, producing abnormally high levels of non-ceruloplasmin-bound copper, the determinant of the pathogenic process causing brain and hepatic damage and dysfunction. Although the disease is invariably fatal without medication, it is treatable and many of its adverse effects are reversible. Diagnosis is difficult due to the large range and severity of symptoms. A high index of suspicion is required as patients may have only a few of the many possible biomarkers. The genetic prevalence of ATP7B variants indicates higher rates in the population than are currently diagnosed. Treatments have evolved from chelators that reduce stored copper to zinc, which reduces the toxic levels of circulating non-ceruloplasmin-bound copper. Zinc induces intestinal metallothionein, which blocks copper absorption and increases excretion in the stools, resulting in an improvement in symptoms. Two meta-analyses and several large retrospective studies indicate that zinc is equally effective as chelators for the treatment of WD, with the advantages of a very low level of toxicity and only the minor side effect of gastric disturbance. Zinc is recommended as a first-line treatment for neurological presentations and is gaining acceptance for hepatic presentations. It is universally recommended for lifelong maintenance therapy and for presymptomatic WD.

Biochemical diagnosis of Wilson's disease: an update

Wilson's disease (WD) is an inherited disorder of copper metabolism caused by mutations in the ATP7B gene. This condition is characterized by the accumulation of copper in the liver and other organs and tissues causing hepatic and neuropsychiatric manifestations. This paper reviews the diagnostic performance and limitations of the biochemical tests commonly used to detect this underdiagnosed disease. It also provides some recommendations and suggests a set of standardized laboratory comments. At present, a rapid, simple, reliable biochemical test that confirms diagnosis of WD is not available. However, diagnosis can be established based on serum ceruloplasmin and urinary copper excretion. Total serum copper should be employed with caution, since it has a low negative predictive value. The use of estimated non-ceruloplasmin-bound copper is not recommended. Nevertheless, measured relative exchangeable copper has very high sensitivity and specificity and emerges as a potential gold standard for the biochemical diagnosis of WD. The development of novel assays for WD detection makes this disorder a potential candidate to be included in newborn screening programs.

Review about Powerful Combinations of Advanced and Hyphenated Sample Introduction Techniques with Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) for Elucidating Trace Element Species in Pathologic Conditions on a Molecular Level

Element analysis in clinical or biological samples is important due to the essential role in clinical diagnostics, drug development, and drug-effect monitoring. Particularly, the specific forms of element binding, actual redox state, or their spatial distribution in tissue or in single cells are of interest in medical research. This review summarized exciting combinations of sophisticated sample delivery systems hyphenated to inductively coupled plasma-mass spectrometry (ICP-MS), enabling a broadening of information beyond the well-established outstanding detection capability. Deeper insights into pathological disease processes or intracellular distribution of active substances were provided, enabling a better understanding of biological processes and their dynamics. Examples were presented from spatial elemental mapping in tissue, cells, or spheroids, also considering elemental tagging. The use of natural or artificial tags for drug monitoring was shown. In the context of oxidative stress and ferroptosis iron, redox speciation gained importance. Quantification methods for Fe2+, Fe3+, and ferritin-bound iron were introduced. In Wilson’s disease, free and exchangeable copper play decisive roles; the respective paragraph provided information about hyphenated Cu speciation techniques, which provide their fast and reliable quantification. Finally, single cell ICP-MS provides highly valuable information on cell-to-cell variance, insights into uptake of metal-containing drugs, and their accumulation and release on the single-cell level.

Eye Involvement in Wilson’s Disease: A Review of the Literature

Wilson’s disease (WD) is an autosomal recessive genetic disorder due to a mutation of the ATP7B gene, resulting in impaired hepatic copper excretion and accumulation in various tissues. Ocular findings are one of the hallmarks of the disease. Many ophthalmological manifestations have been described and new techniques are currently available to improve their diagnosis and to follow their evolution. We have performed a systematic PubMed search to summarize available data of the recent literature on the most frequent ophthalmological disorders associated with WD, and to discuss the newest techniques used for their detection and follow-up during treatment. In total, 49 articles were retained for this review. The most common ocular findings seen in WD patients are Kayser–Fleischer ring (KFR) and sunflower cataracts. Other ocular manifestations may involve retinal tissue, visual systems and eye mobility. Diagnosis and follow-up under decoppering treatment of these ocular findings are generally easily performed with slit-lamp examination (SLE). However, new techniques are available for the precocious detection of ocular findings due to WD and may be of great value for non-experimented ophthalmologists and non-ophthalmologists practitioners. Among those techniques, anterior segment optical coherence tomography (AS-OCT) and Scheimpflug imaging are discussed.

Clinical and Genetic Analysis in Neurological Wilson’s Disease Patients With Neurological Worsening Following Chelator Therapy

Objectives: None of the previous studies have focused on the genetic effect on neurological worsening in neurological Wilson’s disease (WD) patients following chelator therapy. We aimed to evaluate the clinical and genetic role in the occurrence of neurological worsening.

Methods: We retrospectively reviewed the medical records of neurological WD patients who received initial chelator therapy and genetic test. Clinical, laboratory, and genetic data were collected. The genotype was classified into two types: 1) severe mutation genotype: patients who carried at least one of the following three types of mutations: frameshift mutation, splicing mutation, or nonsense mutation; 2) non-severe mutation genotype: patients who only carried missense mutations. Then, the clinical features and genotype of the patients with and without neurological worsening were investigated.

Results: Forty-seven neurological WD patients were identified with a median age at onset of 16.17 years (range 7.75–47 years) and 35 (74.5%) males. The mean interval from onset to diagnosis was 0.6 years (range: 0.5 months-6.25 years). Neurological deterioration was observed in 29 patients (61.7%) and the other 18 patients (38.3%) were stable or improved during anti-copper treatment. The neurological worsening was completely irreversible in 6 cases (20.7%) and partially irreversible in 16 cases (55.2%). The common deteriorated symptoms were as follows: rigidity in 20 cases (69%), speech difficulties in 20 cases (69%)), walking difficulties in 13 cases (44.8%), dysphagia in 9 cases (31%), and salivation in 9 cases (31%). The patients with neurological worsening had significantly younger age (p = 0.028), shorter delayed diagnosis time (p = 0.011), higher rate of dystonia (p = 0.003), and severe mutation genotype (p = 0.036), compared to those without neurological worsening.

Conclusion: We found that younger age of onset, the presence of dystonia, and genotype with severe mutations may be predictive of neurological worsening in the neurological WD patients that received chelator therapy. For those patients, chelator therapy should be given with caution and needs closer observation during follow-up.

Elucidation of Mechanisms in Cu (II) Caused Hypercontraction of Rat Tracheal Rings

Airway smooth muscle contraction is one of the primary factors involved in the initiation and progression of asthma which in turn is regulated by increased cytosolic Ca²⁺ concentration from intracellular stores and through transmembrane ion channels. Calcium-independent factors such as reactive oxygen species (ROS) generation, nitric oxide (NO) depletion and cyclooxygenase (COX) pathways also contribute to tracheal smooth muscle contraction. Studies on copper toxicity suggest significance of this essential micronutrient overdose in acute respiratory disorders, allergic asthma and ciliary motion in tracheal explants. However, the mechanism of copper caused hypercontraction upon direct exposure to tracheal smooth muscle is largely unknown. In this study we investigate the effect of copper exposure on isolated tracheal rings and relative contributions of various factors in acetylcholine-induced contractions. Results obtained suggest that rise in intracellular calcium concentration via voltage-operated Ca²⁺ channel (VOCC), store-operated Ca²⁺ channel (SOCC), stretch-activated channels (SAC) and TRP channel (transient receptor potential channel) activation is the major factor in copper-mediated hypercontraction. ROS generation or COX-dependent pathways do not appear to significantly contribute to Cu²⁺ caused hypercontraction.

Non-invasive diagnosis and follow-up of rare genetic liver diseases

Rare genetic liver diseases can result in multi-systemic damage, which may compromise the patient's prognosis. Wilson's disease and alpha-1 antitrypsin deficiency must be investigated in any patient with unexplained liver disease. Cystic fibrosis screening of new-borns is now implemented in most high-prevalence countries. The diagnosis of these diseases can be strongly suggested with specific non-invasive tests. Molecular analysis gene for these diseases is long and tedious but is recommended to confirm the diagnosis and help for the family screening. Liver biopsy is not systematic and is discussed when it helps diagnosis. Currently, for these three diseases, non-invasive fibrosis markers could identify patients with risk of cirrhosis and complications. Rare genetic liver diseases can result in multi-systemic damage, which may compromise the patient's prognosis. Wilson's disease, must be investigated in any patient with unexplained liver disease and/or unexplained neurological or neuropsychiatric disorders. The diagnosis is based on a combination of clinical, biological features, including copper balance. The exchangeable copper/total copper ratio is a new sensible and specific biological marker, useful for the diagnosis of the disease. Timely diagnosis and treatment will prevent serious complications from the disease. Neurological evaluation and familial screening are essential in patients with Wilson's disease.

Bis-choline tetrathiomolybdate prevents copper-induced blood-brain barrier damage

The blood–brain barrier endothelial cell monolayer becomes permeable to elevated copper loosely bound to albumin, which can be avoided by a high-affinity copper chelator but not by D-penicillamine.

In Wilson disease, excessive copper accumulates in patients’ livers and may, upon serum leakage, severely affect the brain according to current viewpoints. Present remedies aim at avoiding copper toxicity by chelation, for example, by D-penicillamine (DPA) or bis-choline tetrathiomolybdate (ALXN1840), the latter with a very high copper affinity. Hence, ALXN1840 may potentially avoid neurological deterioration that frequently occurs upon DPA treatment. As the etiology of such worsening is unclear, we reasoned that copper loosely bound to albumin, that is, mimicking a potential liver copper leakage into blood, may damage cells that constitute the blood-brain barrier, which was found to be the case in an in vitro model using primary porcine brain capillary endothelial cells. Such blood–brain barrier damage was avoided by ALXN1840, plausibly due to firm protein embedding of the chelator bound copper, but not by DPA. Mitochondrial protection was observed, a prerequisite for blood–brain barrier integrity. Thus, high-affinity copper chelators may minimize such deterioration in the treatment of neurologic Wilson disease.

Wilson's disease: update on pathogenesis, biomarkers and treatments

Wilson's disease is an autosomal-recessive disorder of copper metabolism caused by mutations in ATP7B and associated with neurological, psychiatric, ophthalmological and hepatic manifestations. Decoppering treatments are used to prevent disease progression and reduce symptoms, but neurological outcomes remain mixed. In this article, we review the current understanding of pathogenesis, biomarkers and treatments for Wilson's disease from the neurological perspective, with a focus on recent advances. The genetic and molecular mechanisms associated with ATP7B dysfunction have been well characterised, but despite extensive efforts to identify genotype-phenotype correlations, the reason why only some patients develop neurological or psychiatric features remains unclear. We discuss pathological processes through which copper accumulation leads to neurodegeneration, such as mitochondrial dysfunction, the role of brain iron metabolism and the broader concept of selective neuronal vulnerability in Wilson's disease. Delayed diagnoses continue to be a major problem for patients with neurological presentations. We highlight limitations in our current approach to making a diagnosis and novel diagnostic biomarkers, including the potential for newborn screening programmes. We describe recent progress in developing imaging and wet (fluid) biomarkers for neurological involvement, including findings from quantitative MRI and other neuroimaging studies, and the development of a semiquantitative scoring system for assessing radiological severity. Finally, we cover the use of established and novel chelating agents, paradoxical neurological worsening, and progress developing targeted molecular and gene therapy for Wilson's disease, before discussing future directions for translational research.

Wilson's Disease: Facing the Challenge of Diagnosing a Rare Disease

Wilson disease (WD) is a rare disorder caused by mutations in ATP7B, which leads to the defective biliary excretion of copper. The subsequent gradual accumulation of copper in different organs produces an extremely variable clinical picture, which comprises hepatic, neurological psychiatric, ophthalmological, and other disturbances. WD has a specific treatment, so that early diagnosis is crucial to avoid disease progression and its devastating consequences. The clinical diagnosis is based on the Leipzig score, which considers clinical, histological, biochemical, and genetic data. However, even patients with an initial WD diagnosis based on a high Leipzig score may harbor other conditions that mimic the WD's phenotype (Wilson-like). Many patients are diagnosed using current available methods, but others remain in an uncertain area because of bordering ceruloplasmin levels, inconclusive genetic findings and unclear phenotypes. Currently, the available biomarkers for WD are ceruloplasmin and copper in the liver or in 24 h urine, but they are not solid enough. Therefore, the characterization of biomarkers that allow us to anticipate the evolution of the disease and the monitoring of new drugs is essential to improve its diagnosis and prognosis.

Total and Exchangeable Copper Assay Using Inductively Coupled Plasma Mass Spectrometry and Establishment of a Pediatric Reference Interval

CONTEXT.—

Recently, an exchangeable copper (CuEXC) assay has been suggested as a robust and feasible diagnostic tool for Wilson disease (WD). Although WD is a disorder that requires lifelong treatment and monitoring, few data are currently available regarding the status of copper levels in children.

OBJECTIVE.—

To evaluate the performance of copper assays and establish a reference interval for total copper and CuEXC in the pediatric population.

DESIGN.—

Serum samples from children aged 1-5 (n = 122), 6-12 (n = 125), and 13-18 years (n = 120) were analyzed. Total copper and CuEXC concentrations were directly measured using inductively coupled plasma mass spectrometry, and relative CuEXC levels were calculated. Total copper reference intervals, CuEXC levels, and relative CuEXC levels were determined based on the 2.5th and 97.5th percentiles of the data with 90% confidence intervals.

RESULTS.—

There were significant differences in the median concentrations of total copper and relative CuEXC among the age groups. Reference intervals determined for total copper were 82 to 167, 75 to 139, and 64 to 133 μg/dL for children aged 1 to 5, 6 to 12, and 13 to 18 years, respectively. The reference intervals for CuEXC were 4.29 to 9.79, 4.02 to 9.09, and 3.55 to 8.25 μg/dL for children aged 1 to 5, 6 to 12, and 13 to 18 years, respectively. Among 11 patients with suspected WD, relative CuEXC values were elevated in all 3 diagnosed with WD.

CONCLUSIONS.—

The pediatric reference intervals derived in this study are expected to be useful for the diagnosis, differential diagnosis, treatment, and monitoring of pediatric patients with WD.

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.

Considerations for optimizing Wilson's disease patients' long-term follow-up

Wilson's disease is a sistemic genetic disease caused by the excessive accumulation of copper. The first and main involvement is in the liver, which can range from mild and transient elevation of transaminases to the onset of an overt cirrhosis or acute liver failure. It is known that up to 20-30% of these patients may evolve to liver cirrhosis during follow-up. In clinical practice, liver fibrosis is assessed mainly by using indirect and non-invasive tools (laboratory tests, liver elastography, ultrasound), similar to other prevalent chronic liver diseases. However, despite the fact that liver elastography is a valuable tool in general hepatology, the evidence of its usefulness and accuracy in Wilsońs disease is scarce. This review summarizes the available scientific data and their limitations in Wilson's disease.

Plasma Neurofilament Light as a Biomarker of Neurological Involvement in Wilson's Disease

BACKGROUND

Outcomes are unpredictable for neurological presentations of Wilson's disease (WD). Dosing regimens for chelation therapy vary and monitoring depends on copper indices, which do not reflect end-organ damage.

OBJECTIVE

To identify a biomarker for neurological involvement in WD.

METHODS

Neuronal and glial-specific proteins were measured in plasma samples from 40 patients and 38 age-matched controls. Patients were divided into neurological or hepatic presentations and those with recent neurological presentations or deterioration associated with non-adherence were subcategorized as having active neurological disease. Unified WD Rating Scale scores and copper indices were recorded.

RESULTS

Unlike copper indices, neurofilament light (NfL) concentrations were higher in neurological than hepatic presentations. They were also higher in those with active neurological disease when controlling for severity and correlated with neurological examination subscores in stable patients.

CONCLUSION

NfL is a biomarker of neurological involvement with potential use in guiding chelation therapy and clinical trials for novel treatments. © 2020 University College London. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

[Retrospective cross-sectional study based on nationwide data of drug prescriptions and contractional data of outpatient offices regarding Morbus Wilson's disease]

INTRODUCTION

 In this article, the prevalence of the Morbus Wilson disease in Germany is determined. This is based on nationwide data of drug prescriptions and contractional data of outpatient offices. The prevalence is set in ratio to the found prevalence of prescriptions in Germany.

METHOD

 The descriptive evaluation is based on the database of the Central Research Institute of Ambulatory Health Care (Zi) in Germany. Additionally, data of the Federal Office of Statistics regarding inpatient treatment are available.

RESULTS

 It can be seen that there is a notable difference between the prevalence of patients undergoing therapy and the patients with verified diagnoses. In total, prevalence is increasing. The incidence on hand and the given dynamic of the patient population could indicate that, possibly, there is an increased rate of misdiagnosis in the first year of diagnosis. According to data, the hepatic form is the more often diagnosed form. The human genetic diagnostic increases, on average, are most distinct.

ATTRIBUTES

 Wilson Disease, Prevalence, Incidence, Trientine, Trientintetrahydrochlorid, D-Penicillamin, Zinc acetat, Zinc.

Pediatric Wilson Disease Presenting as Acute Liver Failure: An Individual Patient Data Meta-analysis

OBJECTIVES

Wilson disease (WD) presenting as acute liver failure (ALF) is rare and typically fatal without liver transplantation (LT). Its rarity has hindered comprehensive studies. We undertook an individual patient data meta-analysis to characterize a cohort of pediatric patients presenting with ALF whose final diagnosis was WD to examine outcomes and identify predictors of poor outcomes.

METHODS

Database searches were conducted in PubMed, ScienceDirect, and Google Scholar, restricted to English-language articles published between January 1984 and May 2018. Articles were excluded if pediatric (<18 years old) data were not extractable or if LT was not readily available at reporting institutions. Extracted data included clinical and biochemical characteristics, genotype, treatment, and outcome.

RESULTS

Data were available on 249 subjects from 52 articles, plus 7 additional subjects identified from our institution's WD database (N = 256). Females represented 69% (n = 170/245). Median age at presentation was 13.4 years (n = 204, range 4.0-17.9). Of the total 256 subjects, 87% underwent LT, 11% achieved spontaneous recovery and 2% died before LT. International normalized ratio >2.0 at presentation was a predictor of LT/death (odds ratio 7.6, 95% confidence interval 1.5-28), with a trend observed for hepatic encephalopathy (HE) (odds ratio 4.18, 95% confidence interval 0.99-18). Arithmetic diagnostic scores proved inferior in the pediatric age-bracket compared to adults.

CONCLUSIONS

This large international pediatric cohort has permitted an individual patient data analysis of WD presenting as ALF. Notably, 11% of subjects achieved spontaneous survival; the rest required LT. Coagulopathy (international normalized ratio >2:0) and HE at presentation heralded poor outcomes. Further prospective studies may identify additional early predictors of outcomes.

Sleep disorders in Wilson's disease

BACKGROUND/OBJECTIVES

Wilson's disease (WD) is a rare genetic disorder that leads to copper overload, mainly in the liver then, in the brain. Patients with WD often complain about sleep disorders. We aimed to explore them.

PATIENTS/METHODS

Sleep complaints and disease symptoms were compared in 40 patients with WD (20 patients with hepatic phenotype matched to 20 neurologic one) and 40 age, sex and BMI matched healthy controls.

RESULTS

Patients with WD had more frequently (32.5 vs 10.0%, p < 0.05) and more severe (10.5 ± 6.0 vs 7.6 ± 4.8, p < 0.01) insomnia than controls and insomnia was more severe in neurologic than hepatic form of the disease (12.25 ± 5.89 vs 8.73 ± 5.8, p < 0.05). Insomnia severity was correlated with the severity of depressive symptoms (r = 0.53, p < 0.001). Compared to controls, patients reported more difficulties staying asleep and more consequences of insomnia on their quality of life. REM sleep behavior disorder was more frequent in WD (20 vs 0%, p = 0.005) than controls. Patients complained more frequently of nycturia (22.8 vs 7.6%, p = 0.003) than controls. Patients did not differ from controls for sleepiness, restless legs syndrome and obstructive sleep apnea syndrome. Patients did not report cataplexia.

CONCLUSION

In patients with WD, insomnia and REM sleep behavior disorder are the two main sleep complaints. Insomnia is more frequent in neurologic than hepatic form of the disease. Severity of insomnia is associated with the severity of depressive symptoms.

Liver transplantation as a rescue therapy for severe neurologic forms of Wilson disease

OBJECTIVE

To evaluate the effect of liver transplantation (LT) in patients with Wilson disease (WD) with severe neurologic worsening resistant to active chelation.

METHODS

French patients with WD who underwent LT for pure neurologic indication were retrospectively studied. Before LT and at the last follow-up, neurologic impairment was evaluated with the Unified Wilson's Disease Rating Scale (UWDRS) score, disability with the modified Rankin Scale (mRS) score, and hepatic function with the Model for End-stage Liver Disease score, together with the presence of a Kayser-Fleischer ring (KFR), brain MRI scores, and copper balance. The survival rate and disability at the last follow-up were the coprimary outcomes; evolution of KFR and brain MRI were the secondary outcomes. Prognosis factors were further assessed.

RESULTS

Eighteen patients had LT. All were highly dependent before LT (median mRS score 5). Neurologic symptoms were severe (median UWDRS score 105), dominated by dystonia and parkinsonism. The cumulated survival rate was 88.8% at 1 year and 72.2% at 3 and 5 years. At the last follow-up, 14 patients were alive. Their mRS and UWDRS scores improved (p < 0.0001 and p = 0.0003). Eight patients had a major improvement (78% decrease of the UWDRS score), 4 a moderate one (41% decrease), and 2 a stable status. KFR and brain MRI scores improved (p = 0.0007). Severe sepsis (p = 0.011) and intensive care unit admission (p = 0.001) before LT were significantly associated with death.

CONCLUSIONS

LT is a rescue therapeutic option that should be carefully discussed in selected patients with neurologic WD resistant to anticopper therapies (chelators or zinc salts) as it might allow patients to gain physical independency with a reasonable risk.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that for patients with WD with severe neurologic worsening resistant to active pharmacologic therapy, LT might decrease neurologic impairment.

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.

A Responsive Magnetic Resonance Imaging Contrast Agent for Detection of Excess Copper(II) in the Liver In Vivo

The design, synthesis, and properties of a new gadolinium-based copper-responsive magnetic resonance imaging (MRI) contrast agent is presented. The sensor (GdL₁) has high selectivity for copper ions and exhibits a 43% increase in r₁ relaxivity (20 MHz) upon binding to 1 equiv of Cu²⁺ in aqueous buffer. Interestingly, in the presence of physiological levels of human serum albumin (HSA), the r₁ relaxivity is amplified further up to 270%. Additional spectroscopic and X-ray absorption spectroscopy (XAS) studies show that Cu²⁺ is coordinated by two carboxylic acid groups and the single amine group on an appended side chain of GdL₁ and forms a ternary complex with HSA (GdL₁-Cu²⁺-HSA). T₁-weighted in vivo imaging demonstrates that GdL₁ can detect basal, endogenous labile copper(II) ions in living mice. This offers a unique opportunity to explore the role of copper ions in the development and progression of neurological diseases such as Wilson's disease.

Neurologic impairment in Wilson disease

Neurologic symptoms in Wilson disease (WD) appear at an older age compared to hepatic symptoms and manifest in patients with misdiagnosed liver disease, in patients when the hepatic stage is clinically silent, in the case of non-compliance with anti-copper treatment, or with treatment failure. Neurologic symptoms in WD are caused by nervous tissue damage that is primarily a consequence of extrahepatic copper toxicity. Copper levels in brain tissues as well as cerebrospinal fluid (CSF) are diffusely increased by a factor of 10 and its toxicity involves various mechanisms such as mitochondrial toxicity, oxidative stress, cell membrane damage, crosslinking of DNA, and inhibition of enzymes. Excess copper is initially taken-up and buffered by astrocytes and oligodendrocytes but ultimately causes dysfunction of blood-brain-barrier and demyelination. Most severe neuropathologic abnormalities, including tissue rarefaction, reactive astrogliosis, myelin palor, and presence of iron-laden macrophages, are typically present in the putamen while other basal ganglia, thalami, and brainstem are usually less affected. The most common neurologic symptoms of WD are movement disorders including tremor, dystonia, parkinsonism, ataxia and chorea which are associated with dysphagia, dysarthria and drooling. Patients usually manifest with various combinations of these symptoms while purely monosymptomatic presentation is rare. Neurologic symptoms are largely reversible with anti-copper treatment, but a significant number of patients are left with residual impairment. The approach for symptomatic treatment in WD is based on guidelines for management of common movement disorders. The vast majority of WD patients with neurologic symptoms have abnormalities on brain magnetic resonance imaging (MRI). Pathologic MRI changes include T2 hyperintensities in the basal ganglia, thalami and white matter, T2 hypointensities in the basal ganglia, and atrophy. Most importantly, brain damage and neurologic symptoms can be prevented with an early initiation of anti-copper treatment. Introducing population WD screening, e.g., by exome sequencing genetic methods, would allow early treatment and decrease the neurologic burden of WD.

Challenges in the diagnosis of Wilson disease

The understanding and management of Wilson disease (WD) have dramatically improved since the first description of the disease by K. Wilson more than a century ago. However, the persistent long delay between the first symptoms and diagnosis emphasizes challenges in diagnosing earlier this copper overload disorder. As a treatable disease, WD should be detected early in the course of the disease by any health professionals at any care level, but the rare prevalence of the disease explains the lack of awareness of referring physicians. The most important challenge is to train physicians to recognize atypical or rare symptoms of WD that will lead to discuss the diagnosis more systematically. Atypia can come from the age of onset, the liver [non-alcoholic steatohepatitis (NASH) presentation], the central or peripheral nervous system (neuropathy, epilepsy, sleep disorders…) or may be due to lesions of other organs (renal manifestations, osteo-articular disorders or endocrine disturbances). Isolated biological anomalies, rare radiological findings or inadequate interpretation of copper test may also lead to misdiagnosis. The second challenge is to confirm the diagnosis faster and more effectively so as not to delay the initiation of treatment, and expand family screening as the genetic prevalence is higher than previously expected. Generalization of the exchangeable copper assay and the next generation sequencing (NGS) are two promising ways to overcome this ultimate challenge. By drawing attention to the earliest and rare symptoms and to new biomarkers and diagnostic tools, we hope that this article will increase diagnostic awareness and reduce delays so that patients can start their treatment earlier in the course of the illness and thus have a better disease prognosis.

Current anti-copper therapies in management of Wilson disease

In Wilson disease (WD) severity of disease can vary widely, depending on time of diagnosis. Early treatment can prevent the development of symptoms in patients. In all patients, lifelong medical treatment is indicated. Currently available medical regimens include the copper chelators for example D-penicillamine (DPA) or trientine (TETA), acting to increase copper excretion and zinc salts (ZS), which reduce copper uptake. In this chapter, we discuss considerations regarding choice of drug and safety limitations.

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.