Relative exchangeable copper: a new highly sensitive and highly specific biomarker for Wilson's disease diagnosis

The cost implications of Wilson disease among hospitalized patients: analysis of USA hospitals

BACKGROUND AND AIM

In this study, we used a national cohort of patients with Wilson's disease (WD) to investigate the admissions, mortality rates, and costs over the captured period to assess specific subpopulations at higher burden.

METHODS

Patients with WD were selected using 2016-2019 National Inpatient Sample (NIS). The weighted estimates and patient data were stratified using demographics and medical characteristics. Regression curves were graphed to derive goodness-of-fit for each trend from which R2 and P values were calculated.

RESULTS

Annual total admissions per 100 000 hospitalizations due to WD were 1075, 1180, 1140, and 1330 (R2 = 0.75; P = 0.13) from 2016 to 2019. Within the demographics, there was an increase in admissions among patients greater than 65 years of age (R2 = 0.90; P = 0.05) and White patients (R2 = 0.97; P = 0.02). Assessing WD-related mortality rates, there was an increase in the mortality rate among those in the first quartile of income (R2 = 1.00; P < 0.001). The total cost for WD-related hospitalizations was $20.90, $27.23, $24.20, and $27.25 million US dollars for the years 2016, 2017, 2018, and 2019, respectively (R2 = 0.47; P = 0.32). There was an increasing total cost trend for Asian or Pacific Islander patients (R2 = 0.90; P = 0.05). Interestingly, patients with cirrhosis demonstrated a decreased trend in the total costs (R2 = 0.97; P = 0.02).

CONCLUSION

Our study demonstrated that certain ethnicity groups, income classes and comorbidities had increased admissions or costs among patients admitted with WD.

Wilson's Disease with Acute Hepatic Onset: How to Diagnose and Treat It

Wilson's disease (WD) with acute onset poses a diagnostic challenge because it is clinically indistinguishable from other acute liver diseases. In addition, serum ceruloplasmin and urinary copper excretion, the first-line diagnostic tools for WD, can show false positive results in the case of acute liver failure, and the diagnostic role of genetic analysis is limited by the time required to perform it. In the case of fulminant onset, there is a clear indication of liver transplantation. "New Wilson Index" is frequently used to discriminate between patients who need liver transplantation versus those who can be successfully managed by medical treatment, but its reliability remains controversial. Timely referral of patients with acute liver failure due to WD may be a key factor in improving patient survival. Although liver transplant very often represents the only chance for such patients, maximum effort should be made to promote survival with a native liver. The management of these aspects of WD is still a matter of debate and will be the subject of this review.

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.

Recent advances in the diagnosis and management of Wilson's disease

In this editorial, the reader will be updated on novel epidemiological, diagnostic, and therapeutical proposals in the field of Wilson disease.

Semi-synthetic human albumin isoforms: Production, structure, binding capacities and influence on a routine laboratory test

Human Serum Albumin (HSA) undergoes Post-Translational-Modifications (PTMs) leading to isoforms affecting its oncotic and non-oncotic properties. HSA is comprised of several isoforms whose abundance may vary with pathologies such as diabetes, kidney and liver diseases. Studying their impact separately may help to understand their sources and potential pathogenicity and further their evaluation as biomarkers. The present study examined semi-synthetic HSA isoforms to investigate independently their structure by means of advanced mass spectrometry techniques (LC-TOF-MS and ICP-MS), influence on the HSA binding/antioxidant activities using a binding capacity test, and potential impact on albumin quantification by a routine immunoturbidimetric assay. Applying different chemical reactions to a commercial HSA solution, we obtained different solutions enriched up to 53 % of native HSA, 78 % of acetylated HSA, 71 % of cysteinylated HSA, 94 % of oxidized HSA, 58 % of nitrosylated HSA and 96 % of glycated HSA, respectively. Moreover, the semi-synthetic isoforms showed differently altered binding capacities for a panel of ligands (Cu, Cd, Au, Ds and L-T4). Furthermore, immunoturbidimetry was found to be insensitive to the presence and abundance of the different isoforms. The fully characterized semi synthetic HSA isoforms obtained should be useful to further investigate their pathogenicity and potential roles as biomarkers.

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.

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.

Dysregulation of Copper Metabolism in a Patient With Acute-on-Chronic Liver Failure Worked up for Fulminant Wilson Disease

Wilson disease (WD) is estimated present in 6%-12% of patients younger than 40 years hospitalized with acute liver failure (ALF). Fulminant WD carries a poor prognosis without treatment. A 36-year-old man with HIV, chronic hepatitis B virus, and alcohol use had ceruloplasmin 6.4 mg/dL and 24-hour urine copper 180 μg/L. WD workup was otherwise negative, including ophthalmic examination, hepatic copper quantification, ATP7B sequencing, and brain MRI. ALF commonly features copper dysregulation. Few studies on WD biomarkers have included fulminant WD. Our patient with WD biomarkers and other causes of liver failure highlights the need to study copper dysregulation in ALF.

Medical care of patients with Wilson disease in Germany: a multidisciplinary survey among university centers

BACKGROUND

Wilson disease (WD) is a rare, hereditary disorder of copper metabolism. Due to its variable symptoms and manifestations, diagnosis remains challenging. Affected patients must obtain lifelong medical treatment, as the disease is fatal if untreated. Patients require continuous monitoring, but little is known about the care of these patients in Germany. Therefore, we analyzed the medical care of WD patients at German university centers. We sent a questionnaire containing 20 questions to a total of 108 departments of pediatrics, neurology and gastroenterology in 36 university hospitals. Our questions referred to the characteristics of WD patients at the different sites and internal procedures regarding diagnosis, therapy and follow-up. A descriptive statistical analysis was performed.

RESULTS

Sixty-three departments (58%) returned our questionnaire. In total, approximately one-third of the estimated WD patients in Germany are seen annually in the outpatient clinics of these departments (approx. 950 patients). There are only a few departments which treat patients in a multidisciplinary setting (12%). Our survey revealed that for diagnosis, 51% of all departments used an algorithm based on the Leipzig score as recommended by international guidelines. Most departments apply essential parameters recommended by WD guidelines. Routine monitoring is performed at least biannually by 84% of the departments, and standard investigations for monitoring are regularly applied. A routine family screening is performed by 84% of all departments. A reduction in medical therapy during pregnancy is recommended by 46% of the departments. Only 14% suggested that WD patients should not breastfeed. Liver transplantation (LT) due to WD is a rare but repeatedly occurring event. Most departments of gastroenterology (72%) reported at least one patient with LT within the last decade.

CONCLUSIONS

Medical care of WD patients at German university centers follows the recommendations set forth by international guidelines, but only a few centers treat significant numbers of patients. The surveillance of patients does not follow specified standards, but most departments adhere to the accepted guidelines. The formation of central units and networks in a multidisciplinary setting should be evaluated to improve the care of WD patients.

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.

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.

[Wilson's disease: overview]

Wilson's disease (WD) is an uncommon hereditary disorder caused by a deficiency in the ATP7B transporter. The protein codified by this gene facilitates the incorporation of the copper into ceruloplasmin. Therefore, WD accumulates copper primary in the liver and secondary in other organs, such as the central nervous system. It represents a wide spectrum of disease, ranging from being asymptomatic in some patients to promote an acute liver failure in others. The diagnosis requires a combination of clinical signs and symptoms, as well as some diagnostic tests such as the measurement of serum ceruloplasmin, the urinary excretion of copper, the liver biopsy or the genetic testing. The treatment must be maintained lifelong and includes some drugs such as chelating agents (penicillamine and trientine) and inhibitors of the copper absorption (zinc salts). Lastly, the liver transplant should be an option for patients with end-stage liver disease.

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.

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.

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: An Update on the Diagnostic Workup and Management

Wilson's disease (WD) is a rare autosomal recessive disorder of hepatocellular copper deposition. The diagnostic approach to patients with WD may be challenging and is based on a complex set of clinical findings that derive from patient history, physical examination, as well as laboratory and imaging testing. No single examination can unequivocally confirm or exclude the disease. Timely identification of signs and symptoms using novel biomarkers and modern diagnostic tools may help to reduce treatment delays and improve patient prognosis. The proper way of approaching WD management includes, firstly, early diagnosis and prompt treatment introduction; secondly, careful and lifelong monitoring of patient compliance and strict adherence to the treatment; and, last but not least, screening for adverse effects and evaluation of treatment efficacy. Liver transplantation is performed in about 5% of WD patients who present with acute liver failure at first disease presentation or with signs of decompensation in the course of liver cirrhosis. Increasing awareness of this rare inherited disease among health professionals, emphasizing their training to consider early signs and symptoms of the illness, and strict monitoring are vital strategies for the patient safety and efficacy of WD therapy.

Non-Ceruloplasmin Copper as a Stratification Biomarker of Alzheimer's Disease Patients: How to Measure and Use It

Alzheimer's disease (AD) is a type of dementia very common in the elderly. A growing body of recent evidence has linked AD pathogenesis to copper (Cu) dysmetabolism in the body. In fact, a subset of patients affected either by AD or by its prodromal form known as Mild Cognitive Impairment (MCI) have been observed to be unable to maintain a proper balance of Cu metabolism and distribution and are characterized by the presence in their serum of increased levels of Cu not bound to ceruloplasmin (non-ceruloplasmin Cu). Since serum non-ceruloplasmin Cu is a biomark- er of Wilson's disease (WD), a well-known condition of Cu-driven toxicosis, in this review, we pro- pose that in close analogy with WD, the assessment of non-ceruloplasmin Cu levels can be exploit- ed as a cost-effective stratification and susceptibility/risk biomarker for the identification of some AD/MCI individuals. The approach can also be used as an eligibility criterion for clinical trials aim- ing at investigating Cu-related interventions against AD/MCI.

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.

A fit-for-purpose copper speciation method for the determination of exchangeable copper relevant to Wilson's disease

Exchangeable copper (CuEXC), mainly comprised copper (Cu) bound to albumin, has been proposed as a specific marker of Cu overload in Wilson's disease (WD). To the author's knowledge, there are no methods capable of determining reliably CuEXC to meet the requirements and challenges faced by a clinical trial. The present work describes a novel speciation strategy for the determination of the main Cu-species in human serum by anion-exchange high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). A label-free protein quantification approach was conducted where the concentration of Cu associated to the protein fraction was based on its relative peak area distribution and the total Cu concentration in the sample. Such a methodology was characterized in terms of selectivity, sensitivity, precision, and robustness. Due to the lack of speciated Cu-reference materials, protein recovery was assessed by comparison with that of species-specific (SS) isotope dilution (ID). For this, a double SS HPLC-ICP-IDMS method for Cu-albumin was developed and presented here for the first time. Three human sera (two frozen LGC8211 and ERM®-DA250a, and the lyophilised Seronorm™ Human) were analyzed using both the relative and ID quantification methods. The validated relative approach, with relative expanded uncertainties (k = 2) between 5.7 and 10.1% for Cu-albumin concentrations ranging from 112 to 455 μg kg^-1 Cu, was found to be able to discriminate between healthy and WD populations in terms of Cu-albumin content. Also, using such methodology, underestimation of CuEXC by the classical EDTA/ultrafiltration method was demonstrated. The methodology developed in this work will be invaluable for quality control assessment and WD drug monitoring. This work describes a Cu-protein quantification approach for the determination of exchangeable Cu relevant to Wilson's Disease.

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.

A luminescent ATCUN peptide variant with enhanced properties for copper(II) sensing in biological media

The measurement of labile Cu^II in biological samples is fundamental for understanding Cu metabolism and has been emerging as a promising diagnostic marker for Cu-related pathologies such as Wilson's and Alzheimer's diseases. The use of fluorescent chelators may be useful to circumvent separation steps employed by current methods. For this purpose, we recently designed a selective and suited-affinity turn-off luminescent probe based on a peptide bearing the Cu^II-binding Xxx-Zzz-His (Amino-Terminal Cu^II- and Ni^II-binding, ATCUN) motif and a Tb^III-DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) complex. Here, we present an analogue probe bearing the ATCUN motif variant Xxx-His-His. This probe showed much faster response in biologically-relevant media and higher stability than the previous motif at low pH. These features could be beneficial to the measurement of dynamic Cu^II fluctuations and the application in slightly acidic media, such as urine.

Recent advances in Wilson disease

Wilson disease (WD) is rare genetic disorder that presents with varied phenotype that can at times make the diagnosis challenging. Medical treatments are available, but there are still unmet needs for patients. Since life-long therapy is necessary, adherence to medical therapy and best practices for monitoring and individualizing therapy continue to evolve. Studies are ongoing that address some of these issues. In the current review we focused our attention to recent advances in the diagnosis of WD, current medical treatments, future potential therapies and treatment monitoring. We include discussion of new methodology for detection and quantitation of ophthalmologic signs of WD, new brain imaging modalities for early detection of neurologic involvement in patients and potential new diagnostic methodology using blood samples that may be applicable to newborn screening and adult disease diagnosis. In addition, there are new strategies aimed at improving adherence and outcomes with currently available therapies, including once daily chelation dosing and discussion of the efficacy of different zinc salt compounds. With respect to new therapies with different mechanisms of action, we discuss studies on Bis-choline tetrathiomolybdate (TTM) in patients, pre-clinical studies of a novel chelator methanobactin and other animal studies exploring cures for WD with gene therapy using adeno-associated vectors (AAVs) that introduce ATP7B into liver cells. There are also promising advances in the more accurate measurement of non-ceruloplasmin bound copper and exchangeable copper in the circulation which would potentially help with monitoring and individualization of treatment and possibly play a role in future disease diagnosis.

Management Perspective of Wilson's Disease: Early Diagnosis and Individualized Therapy

Wilson's disease (WD) is an inherited disease caused by mutations in ATP7B and is characterized by the pathological accumulation of copper in the liver and brain. Common clinical manifestations of WD include a wide range of liver disease and neurological symptoms. In some patients, psychiatric symptoms may be the only manifestation at the time of diagnosis. The clinical features of WD are highly variable and can mimic any disease of internal medicine. Therefore, for unexplained medical diseases, the possibility of WD should not be ignored. Early diagnosis and treatment can improve the prognosis of WD patients and reduce disability and early death. Gene sequencing is becoming a valuable method to diagnose WD, and if possible, all WD patients and their siblings should be genetically sequenced. Copper chelators including D-penicillamine, trientine, and dimercaptosuccinic acid can significantly improve the liver injury and symptoms of WD patients but may have a limited effect on neurological symptoms. Zinc salts may be more appropriate for the treatment of asymptomatic patients or for the maintenance treatment of symptomatic patients. High-quality clinical trials for the drug treatment of WD are still lacking, therefore, individualized treatment options for patients are recommended. Individualized treatment can be determined based on the clinical features of the WD patients, efficacy and adverse effects of the drugs, and the experience of the physician. Liver transplantation is the only effective method to save patients with acute liver failure or with severe liver disease who fail drug treatment.

The blood copper isotopic composition is a prognostic indicator of the hepatic injury in Wilson disease

Wilson disease (WD) is an autosomal recessive disorder of copper (Cu) metabolism. The gene responsible for WD, ATP7B, is involved in the cellular transport of Cu, and mutations in the ATP7B gene induce accumulation of Cu in the liver and ultimately in the brain. In a pilot study, the natural variations of copper stable isotope ratios (⁶⁵Cu/⁶³Cu) in the serum of WD patients have been shown to differ from that of healthy controls. In the present study, we challenged these first results by measuring the ⁶⁵Cu/⁶³Cu ratios in the blood of treated (n = 25), naïve patients (n = 11) and age matched healthy controls (n = 75). The results show that naïve patients and healthy controls exhibit undistinguishable ⁶⁵Cu/⁶³Cu ratios, implying that the Cu isotopic ratio cannot serve as a reliable diagnostic biomarker. The type of treatment (d-penicillamine vs. triethylenetetramine) does not affect the ⁶⁵Cu/⁶³Cu ratios in WD patients, which remain constant regardless of the type and duration of the treatment. In addition, the ⁶⁵Cu/⁶³Cu ratios do not vary in naïve patients after the onset of the treatment. However, the ⁶⁵Cu/⁶³Cu ratios decrease with the degree of liver fibrosis and the gradient of the phenotypic presentation, i.e. presymptomatic, hepatic and neurologic. To get insights into the mechanisms at work, we study the effects of the progress of the WD on the organism by measuring the Cu concentrations and the ⁶⁵Cu/⁶³Cu ratios in the liver, feces and plasma of 12 and 45 week old Atp7b^-/- mice. The evolution of the ⁶⁵Cu/⁶³Cu ratios is marked by a decrease in all tissues. The results show that ⁶³Cu accumulates in the liver preferentially to ⁶⁵Cu due to the preferential cellular entry of ⁶³Cu and the impairment of the ⁶³Cu exit by ceruloplasmin. The hepatic accumulation of monovalent ⁶³Cu⁺ is likely to fuel the production of free radicals, which is potentially an explanation of the pathogenicity of WD. Altogether, the results suggest that the blood ⁶⁵Cu/⁶³Cu ratio recapitulates WD progression and is a potential prognostic biomarker of WD.

Assay in serum of exchangeable copper and total copper using inductively coupled plasma mass spectrometry (ICP-MS): development, optimisation and evaluation of a routine procedure

The assay in serum of non-caeruloplasmin copper, as exchangeable copper after complexation with EDTA (ExCu) and total copper has been evaluated and compared in patients with varying c-reactive protein(CRP). Measurement of ExCu and total copper, range 0.2-47.2 µmol/L, was developed using ICP-MS. The chelating agents EDTA and TEPA were compared over 0.0-10 g/L after incubation with serum for 60 mins followed by ultrafiltration with Amicon 10 kDa filter. The assay for ExCu was optimised with EDTA 3 g/L (8.1 mmol/L) maintained at pH 7.0-8.0 before ultrafiltration. TEPA was not as selective in chelation of copper. Patients n = 82 were studied in relation to changes in inflammatory marker CRP and a group of patients n = 37 with normal CRP. The ExCu assay gave excellent recoveries (94-102 % but poor recovery for free uncomplexed copper), good repeatability, limit of quantitation 0.19 µmol/l with a provisional reference range 0.48 to 1.63 µmol/L (n = 37 patients). The range for relative exchangeable copper (exchangeable copper divided by total serum copper) was 2.49 to 9.96 %. ExCu was elevated in conditions with increased CRP greater than 100 mg/L suggesting an effect of inflammation on the free copper fraction. A reliable and reproducible assay for ExCu and total copper has been developed. The upregulated inflammatory state increases the ExCu suggesting excess free copper.

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.

Comprehensive and comparative exploration of the Atp7b−/− mouse plasma proteome

Wilson's disease (WD) is a rare genetic disease caused by mutations in the ATP7B gene. In this study, we used MS-based proteomics to explore the plasma proteome of the Atp7b^−/− mouse, a genetic and phenotypic model for WD.

Is it possible to diagnose fulminant Wilson's disease with simple laboratory tests?

BACKGROUND

Wilson's disease is a rare cause of acute liver failure and is highly fatal without liver transplantation. Fast and accurate diagnostic methods are needed for fulminant Wilson's disease (FWD). In this study, we aimed to develop an early, simple and accurate diagnostic method to differentiate FWD from nonwilsonian acute liver failure (NWALF) causes using routine biochemical data.

METHODS

The medical records of 24 paediatric FWD and 120 paediatric NWALF cases diagnosed at the Department of Pediatric Gastroenterology, Hepatology, and Nutrition between January 2007 and February 2017 were retrospectively reviewed.

RESULTS

Using receiver operator characteristics curve (ROC) analysis, we have determined the best cut-off point for laboratory findings in FWD. Patients meeting these cut-off points were assigned one point and others were assigned zero point. We then formed a new variable consisting of the combination of 14 variables and performed a new ROC analysis. We obtained a cut-off point of ≥4.5 for FWD. The diagnostic performance of the score was characterized by a sensitivity of 0.889, a specificity of 0.879 (P < .001). A scoring system based only on aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, AST/ALT ratio, uric acid and haemoglobin had a best cut-off point of ≥2.5 for FWD, which had a sensitivity of 0.875, a specificity of 0.867 (P < .001).

CONCLUSIONS

Our study demonstrated that biochemical markers offer almost as reliable, fast and accurate diagnosis of FWD as offered by ceruloplasmin and 24-hour urinary copper.

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.

Clinical features and mutational analysis in 114 young children with Wilson disease from South China

Wilson disease (WD) is a rare autosomal recessive disorder caused by mutations in the ATP7B gene. Clinical features and mutational analysis of Chinese children with WD at early age were rarely described. Herein, we retrospectively examined 114 children with WD at the mean of 5.9 years old age at diagnosis. Eight patients developed acute liver failure at mean age of 9.7 years old, 4 of whom died. Among the 114 patients, 86.0% were presymptomatic with isolated elevation of transaminases at diagnosis, 99.1% had decreased ceruloplasmin, and 68.4% had urinary copper excretion over 100 μg/24 hr. Bi-allele pathogenic ATP7B mutations were identified in all patients. Among the 60 mutations detected, 10 were novel, including 7 missense mutations (p.I566N, p.T704I, p.C980F, p.G1030 V, p.A1096Q, p.L1327P, and p.L1373F), 1 nonsense mutation (p.K866X), 1 small insertion (p.Y44LfsX2), and 1 small deletion (p.R1118PfsX10). The most frequent mutations were p.R778L, p.P992L, and p.I1148T, which affected 27.2, 25.4, and 20.2% of the 114 WD children, respectively. The patients carrying p.R778L presented a higher rate of acute liver failure than the patients without p.R778L (9.7% vs. 4.8%). These results will be helpful in establishing early diagnosis of WD at the gene level, offering beneficial information for genetic counseling and providing clues to genotype/phenotype correlation of ATP7B mutations.

Innovative Biomarkers for Alzheimer's Disease: Focus on the Hidden Disease Biomarkers

The criteria for the clinical diagnosis of AD include the analysis of biomarkers of the underlying brain disease pathology; a set of cerebrospinal fluid (CSF) tests, amyloid-β1-42 (Aβ42), total-tau (t-tau), and phosphorylated tau (p-tau), are available and their performance in a clinical setting has been assessed in several studies. Thus, in dementia research, great advances have been made in the discovery of putative biomarkers; however, disappointingly, few of them have been translated into clinically applicable assays. To find biomarkers able to reliably detect AD pathology already at prodromal stages and in blood is even more important. Recent technical breakthroughs have provided ultrasensitive methods that allow the detection of brain-specific proteins in blood. In the present review, we will focus on the usefulness of ultrasensitive technologies for biomarker discovery and trace elements detection; moreover, we will review studies on circulating nano-compartments, a promising novel source of material for molecular diagnostics.

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.

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.

Wilson's Disease: Clinical Practice Guidelines of the Indian National Association for Study of the Liver, the Indian Society of Pediatric Gastroenterology, Hepatology and Nutrition, and the Movement Disorders Society of India

Clinical practice guidelines for Wilson's disease (WD) have been published by the American Association for the Study of Liver Diseases and European Association for the Study of the Liver in 2008 and 2012, respectively. Their focus was on the hepatic aspects of the disease. Recently, a position paper on pediatric WD was published by the European Society of Pediatric Gastroenterology Hepatology and Nutrition. A need was felt to harmonize guidelines for the hepatic, pediatric, and neurological aspects of the disease and contextualize them to the resource-constrained settings. Therefore, experts from national societies from India representing 3 disciplines, hepatology (Indian National Association for Study of the Liver), pediatric hepatology (Indian Society of Pediatric Gastroenterology, Hepatology and Nutrition), and neurology (Movement Disorders Society of India) got together to evolve fresh guidelines. A literature search on retrospective and prospective studies of WD using MEDLINE (PubMed) was performed. Members voted on each recommendation, using the nominal voting technique. The Grades of Recommendation, Assessment, Development and Evaluation system was used to determine the quality of evidence. Questions related to diagnostic tests, scoring system, and its modification to a version suitable for resource-constrained settings were posed. While ceruloplasmin and 24-h urine copper continue to be important, there is little role of serum copper and penicillamine challenge test in the diagnostic algorithm. A new scoring system - Modified Leipzig score has been suggested with extra points being added for family history and serum ceruloplasmin lower than 5 mg/dl. Liver dry copper estimation and penicillamine challenge test have been removed from the scoring system. Differences in pharmacological approach to neurological and hepatic disease and global monitoring scales have been included. Rising bilirubin and worsening encephalopathy are suggested as indicators predicting need for liver transplant but need to be validated. The clinical practice guidelines provide recommendations for a comprehensive management of WD which will be of value to all specialties.

Evaluation of the accuracy of exchangeable copper and relative exchangeable copper (REC) in a mouse model of Wilson's disease

Wilson's disease (WD) is caused by mutations in the ATP7B gene responsible for a toxic copper overload mainly in the liver and the central nervous system. Phenotypic heterogeneity may challenge the diagnostic confirmation. Exchangeable copper (CuEXC) has recently been proposed as a new marker of WD, and its ratio to the total serum copper (Cus), Relative Exchangeable Copper (REC = CuEXC/Cus), as a diagnostic marker. This study aimed to investigate whether this could be confirmed in Atp7b^-/- mice, an engineered WD animal model. Atp7b^-/- (n = 137) and wild type (WT; n = 101) mice were investigated under the same conditions at 6-8, 20, 39, or 50 weeks of age. Twenty-four Atp7b^-/- mice received D-penicillamine treatment from 39 to 50 weeks of age. Serum and liver [histology and intrahepatic copper (IHCu)] data were evaluated. In the WT group, all serum and liver data were normal. Atp7b^-/- livers developed a chronic injury from isolated moderate inflammation (6-8 weeks: 16/33 = 48%) to inflammatory fibrosis with cirrhosis (50 weeks: 25/25 = 100% and 16/25 = 64% respectively). Cus and CuEXC increased until week 39, whereas IHCu and REC were stable with increasing age and much higher than in WT mice (mean ± SD: 669 ± 269 vs. 13 ± 3 μg/g dry liver and 39 ± 12 vs. 11 ± 3%, respectively). A threshold value of 20% for REC provided a diagnostic sensitivity and specificity of 100%, regardless of sex, age, or the use of D-penicillamine. Eleven weeks of 100 mg/kg D-penicillamine reduced liver fibrosis (p = 0.001), IHCu (p = 0.026) and CuEXC (p = 0.175). In conclusion, this study confirms REC as a WD diagnostic marker in a mouse model of chronic liver disease caused by copper overload. Further studies are needed to assess the usefulness of CuEXC to monitor the evolution of WD, particularly during treatment.

Wilson's disease: A 2017 update

Wilson's disease (WD) is characterised by a deleterious accumulation of copper in the liver and brain. It is one of those rare genetic disorders that benefits from effective and lifelong treatments that have dramatically transformed the prognosis of the disease. In Europe, its clinical prevalence is estimated at between 1.2 and 2/100,000 but the genetic prevalence is higher, at around 1/7000. Incomplete penetrance of the gene or the presence of modifier genes may account for the difference between the calculated genetic prevalence and the number of patients diagnosed with WD. The clinical spectrum of WD is broader as expected with mild clinical presentations and late onset of the disease after the age of 40 in 6% of patients. WD is usually suspected when ceruloplasmin and serum copper levels are low and 24h urinary copper excretion is elevated. Recently, a major diagnostic advance was achieved with implementation of the direct assay of "free copper", or exchangeable copper (CuEXC). The relative exchangeable copper (REC) that corresponds to the ratio between CuEXC and total serum copper enables a diagnosis of WD with high sensitivity and specificity when REC>18.5%. Moreover, CuEXC values at diagnosis are a marker of extrahepatic involvement and its severity. A value of >2.08μmol/L is suggestive of corneal and brain involvement (Se=86%, Sp=94%), and the disease will be more clinically and radiologically severe as values rise. The use of FibroScan^® is becoming more widespread to assess liver stiffness measurements in WD patients. 6.6kPa is considered to be a threshold value between mild and moderate fibrosis, whereas a value higher than 8.4 is indicative of severe fibrosis. More studies are now necessary to confirm the usefulness of Fibroscan^® in managing chronic therapy for WD patients. Treatment of this disease is based on an initial active and prolonged chelating phase (with D-Penicillamine or Trientine) followed by maintenance with Trientine or zinc salt. The two major problems that may be encountered are neurological worsening during the initial phase and non-compliance with treatment during maintenance therapy. Liver transplantation is the recommended therapeutic option in WD with acute liver failure or end-stage liver cirrhosis; its indication should be considered when neurological status deteriorates rapidly despite effective chelation. Regular clinical, biological and liver ultrasound follow-up is essential to evaluate efficacy, tolerance and treatment compliance, but also to detect the onset of hepatocellular carcinoma on a cirrhotic liver. There are hopes in the near future with the introduction of a new chelator and inhibitor of copper absorption, tetrathiomolybdate (TTM) and the development of gene therapy.