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

Unusual presentation of Wilson's disease as proximal renal tubular acidosis with isolated phosphaturia

An adolescent girl presented with recurrent lower limb fractures and was managed as osteogenesis imperfecta. Low phosphate levels noted on routine investigation were the clue for the phosphaturia and subsequent diagnosis of proximal renal tubular acidosis (RTA). Further, with a history of jaundice, she was diagnosed with Wilson's disease, which was the underlying cause of proximal RTA with isolated phosphaturia and consequent fractures. Standard treatment for Wilson's disease along with supplementation of oral phosphate and bicarbonate led to complete recovery of fragile bones.

Brain Magnetic Resonance Imaging in Wilson's Disease-Significance and Practical Aspects-A Narrative Review

Wilson's disease (WD) is a genetic disorder of copper metabolism with pathological copper accumulation in many organs, resulting in clinical symptoms, mostly hepatic and neuropsychiatric. As copper accumulates in the brain during WD, and almost 50% of WD patients at diagnosis present with neurological symptoms, neuroimaging studies (especially brain magnetic resonance imaging (MRI)) are part of WD diagnosis. The classical sequences (T1, T2, and fluid-attenuated inversion recovery) were used to describe brain MRI; however, with the development of neuroradiology, several papers proposed the use of new MRI sequences and techniques like susceptibility-weighted images, T2*, diffusion MRI, tractography, volumetric assessment and post-processing brain MRI analysis of paramagnetic accumulation-quantitative susceptibility mapping. Based on these neuroradiological data in WD, currently, brain MRI semiquantitative scale and the pathognomonic neuroradiological brain MRI signs in WD were proposed. Further, the volumetric studies and brain iron accumulation MRI analysis suggested brain atrophy and iron accumulation as biomarkers of neurological WD disease severity. All these results highlight the significance of brain MRI examinations in WD. Due to the extreme progress of these studies, based on the available literature, the authors present the current state of knowledge about the significance, practical aspects, and future directions of brain MRI in WD.

A Novel Mutation in the ATP7B Gene: A Rare Manifestation of Wilson Disease With Liver Failure

Wilson disease is a hereditary disorder which involves anomalous copper metabolism. Typically, the presentation is systemic, involving vital organs such as the liver, kidney, and brain, among others. We report a unique case presenting with solitary organ involvement as acute liver failure with novel ATP7B gene mutation, which has never been reported before.

Copper regulation disturbance linked to oxidative stress and cell death during Zika virus infection in human astrocytes

The Zika virus (ZIKV) caused neurological abnormalities in more than 3500 Brazilian newborns between 2015 and 2020. Data have pointed to oxidative stress in astrocytes as well as to dysregulations in neural cell proliferation and cell cycle as important events accounting for the cell death and neurological complications observed in Congenital Zika Syndrome. Copper imbalance has been shown to induce similar alterations in other pathologies, and disturbances in copper homeostasis have already been described in viral infections. Here, we investigated copper homeostasis imbalance as a factor that could contribute to the cytotoxic effects of ZIKV infection in astrocytes. Human induced pluripotent stem cell-derived astrocytes were infected with ZIKV; changes in the gene expression of copper homeostasis proteins were analyzed. The effect of the administration of CuCl₂ or a copper chelator on oxidative stress, cell viability and percentage of infection were also studied. ZIKV infection leads to a downregulation of one of the transporters mediating copper release, ATP7B protein. We also observed the activation of mechanisms that counteract high copper levels, including the synthesis of copper chaperones and the reduction of the copper importer protein CTR1. Finally, we show that chelator-mediated copper sequestration in ZIKV-infected astrocytes reduces the levels of reactive oxygen species and improves cell viability, but does not change the overall percentage of infected cells. In summary, our results show that copper homeostasis imbalance plays a role in the pathology of ZIKV in astrocytes, indicating that it may also be a factor accounting for the developmental abnormalities in the central nervous system following viral infection. Evaluating micronutrient levels and the use of copper chelators in pregnant women susceptible to ZIKV infection may be promising strategies to manage novel cases of congenital ZIKV syndrome.

Practical insights into chronic management of hepatic Wilson’s disease

Wilson’s disease (WD) is a rare inherited disorder of human copper metabolism, with an estimated prevalence of 1:30000-1:50000 and a broad spectrum of hepatic and neuropsychiatric manifestations. In healthy individuals, the bile is the main route of elimination of copper. In WD patients, copper accumulates in the liver, it is released into the bloodstream, and is excreted in urine. Copper can also be accumulated in the brain, kidneys, heart, and osseous matter and causes damage due to direct toxicity or oxidative stress. Hepatic WD is commonly but not exclusively diagnosed in childhood or young adulthood. Adherent, non-cirrhotic WD patients seem to have a normal life expectancy. Nevertheless, chronic management of patients with Wilson’s disease is challenging, as available biochemical tests have many limitations and do not allow a clear identification of non-compliance, overtreatment, or treatment goals. To provide optimal care, clinicians should have a complete understanding of these limitations and counterbalance them with a thorough clinical assessment. The aim of this review is to provide clinicians with practical tools and suggestions which may answer doubts that can arise during chronic management of patients with hepatic WD. In particular, it summarises current knowledge on Wilson’s disease clinical and biochemical monitoring and treatment. It also analyses available evidence on pregnancy and the role of low-copper diet in WD. Future research should focus on trying to provide new copper metabolism tests which could help to guide treatment adjustments.

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.

Copper Homeostatic Mechanisms and Their Role in the Virulence of Escherichia coli and Salmonella enterica

Copper is an essential micronutrient that also exerts toxic effects at high concentrations. This review summarizes the current state of knowledge on copper handling and homeostasis systems in Escherichia coli and Salmonella enterica. We describe the mechanisms by which transcriptional regulators, efflux pumps, detoxification enzymes, metallochaperones, and ancillary copper response systems orchestrate cellular response to copper stress. E. coli and S. enterica are important pathogens of humans and animals. We discuss the critical role of copper during killing of these pathogens by macrophages and in nutritional immunity at the bacterial-pathogen-host interface. In closing, we identify opportunities to advance our understanding of the biological roles of copper in these model enteric bacterial pathogens.

Mutation analysis of the ATP7B gene and genotype-phenotype correlation in Chinese patients with Wilson disease

AIM

To discover the novel ATP7B mutations in 103 southern Chinese patients with Wilson disease (WD), and to determine the spectrum and frequency of mutations in the ATP7B gene and genotype-phenotype correlation in a large-scale sample of Chinese WD patients.

METHODS

One hundred three WD patients from 101 unrelated families in southern China were enrolled in this study. Genomic DNA was extracted from the peripheral blood. Direct sequencing of all 21 exons within ATP7B was performed. Subsequently, an extensive study of the overall spectrum and frequency of ATP7B mutations and genotype-phenotype correlation was performed in all Chinese patients eligible from the literature, combined with the current southern group.

RESULTS

In 103 patients with WD, we identified 48 different mutations (42 missense mutations, 4 nonsense mutations and 2 frameshifts). Of these, 3 mutations had not been previously reported: c.1510_1511insA, c.2233C>A (p.Leu745Met) and c.3824T>C (p.Leu1275Ser). The c.2333G>T (p.Arg778 Leu) at exon 8, was the most common mutation with an allelic frequency of 18.8%, followed by c.2975C>T (p.Pro992Leu) at exon 13, with an allelic frequency of 13.4%. In the comprehensive study, 233 distinct mutations were identified, including 154 missense mutations, 23 nonsense mutations and 56 frameshifts. Eighty-five variants were identified as novel mutations. The c.2333G>T (p.Arg778 Leu) and c.2975C>T (p.Pro992Leu) were the most common mutations, with allelic frequencies of 28.6% and 13.0%, respectively. Exons 8, 12, 13, 16 and 18 were recognised as hotspot exons. Phenotype-genotype correlation analysis suggested that c.2333G>T (p.Arg778 Leu) was significantly associated with lower levels of serum ceruloplasmin (P = 0.034). c.2975C>T (p.Pro992Leu) was correlated with earlier age of disease onset (P = 0.002). Additionally, we found that the c.3809A>G (p.Asn1270Ser) mutation significantly indicated younger onset age (P = 0.012), and the c.3884C>T (p.Ala1295Val) mutation at exon 18 was significantly associated with hepatic presentation (P = 0.048). Moreover, the patients with mixed presentation displayed the initial WD features at an older onset age than the groups with either liver disease or neurological presentation (P = 0.039, P = 0.015, respectively). No significant difference was observed in the presence of KF rings among the three groups with different clinical manifestations.

CONCLUSION

In this study, we identified three novel mutations in 103 WD patients from the southern part of China, which could enrich the previously established mutational spectrum of the ATP7B gene. Moreover, we tapped into a large-scale study of a Chinese WD cohort to characterise the overall phenotypic and genotypic spectra and assess the association between genotype and phenotype, which enhances the current knowledge about the population genetics of WD in China.

D-Penicillamine: The State of the Art in Humans and in Dogs from a Pharmacological and Regulatory Perspective

Chelant agents are the mainstay of treatment in copper-associated hepatitis in humans, where D-penicillamine is the chelant agent of first choice. In veterinary medicine, the use of D-penicillamine has increased with the recent recognition of copper-associated hepatopathies that occur in several breeds of dogs. Although the different regulatory authorities in the world (United States Food and Drugs Administration-U.S. FDA, European Medicines Agency-EMEA, etc.) do not approve D-penicillamine for use in dogs, it has been used to treat copper-associated hepatitis in dogs since the 1970s, and is prescribed legally by veterinarians as an extra-label drug to treat this disease and alleviate suffering. The present study aims to: (a) address the pharmacological features; (b) outline the clinical scenario underlying the increased interest in D-penicillamine by overviewing the evolution of its main therapeutic goals in humans and dogs; and finally, (c) provide a discussion on its use and prescription in veterinary medicine from a regulatory perspective.

Wilson disease tissue classification and characterization using seven artificial intelligence models embedded with 3D optimization paradigm on a weak training brain magnetic resonance imaging datasets: a supercomputer application

Wilson's disease (WD) is caused by copper accumulation in the brain and liver, and if not treated early, can lead to severe disability and death. WD has shown white matter hyperintensity (WMH) in the brain magnetic resonance scans (MRI) scans, but the diagnosis is challenging due to (i) subtle intensity changes and (ii) weak training MRI when using artificial intelligence (AI). Design and validate seven types of high-performing AI-based computer-aided design (CADx) systems consisting of 3D optimized classification, and characterization of WD against controls. We propose a "conventional deep convolution neural network" (cDCNN) and an "improved DCNN" (iDCNN) where rectified linear unit (ReLU) activation function was modified ensuring "differentiable at zero." Three-dimensional optimization was achieved by recording accuracy while changing the CNN layers and augmentation by several folds. WD was characterized using (i) CNN-based feature map strength and (ii) Bispectrum strengths of pixels having higher probabilities of WD. We further computed the (a) area under the curve (AUC), (b) diagnostic odds ratio (DOR), (c) reliability, and (d) stability and (e) benchmarking. Optimal results were achieved using 9 layers of CNN, with 4-fold augmentation. iDCNN yields superior performance compared to cDCNN with accuracy and AUC of 98.28 ± 1.55, 0.99 (p < 0.0001), and 97.19 ± 2.53%, 0.984 (p < 0.0001), respectively. DOR of iDCNN outperformed cDCNN fourfold. iDCNN also outperformed (a) transfer learning-based "Inception V3" paradigm by 11.92% and (b) four types of "conventional machine learning-based systems": k-NN, decision tree, support vector machine, and random forest by 55.13%, 28.36%, 15.35%, and 14.11%, respectively. The AI-based systems can potentially be useful in the early WD diagnosis. Graphical Abstract.

Wilson disease: copper deficiency and iatrogenic neurological complications with zinc therapy

A 17-year-old female was diagnosed with Wilson disease and commenced on oral zinc therapy. She re-presented 6 months later with a fall and had classical signs of subacute combined degeneration of the spinal cord confirmed on nerve conduction studies, as a result of zinc-induced copper deficiency. After 6 months of copper therapy, she made a complete recovery with no residual neurological deficits. Early detection of zinc-induced copper deficiency and stringent follow-up mechanisms are crucial. Early initiation of copper replacement may both limit and completely reverse neurological deficits.

Diagnostic Performance of Ultrasound Elastography and Serologic Fibrosis Indices for Evaluation of Hepatic Involvement in Wilson Disease

OBJECTIVES

To investigate the diagnostic value of transient elastography (TE), 2-dimensional (2D) shear wave elastography (SWE), and the serologic fibrosis indices aspartate transaminase-to-platelet ratio index (APRI) and Fibrosis-4 (FIB-4) score for Wilson disease (WD).

METHODS

We retrospectively identified patients with a diagnosis of WD who underwent TE and 2D SWE on the same day. Their APRI and FIB-4 scores were calculated. Hepatic involvement was classified into 5 clinical categories (I-V) based on the laboratory findings, hepatic morphologic characteristics on ultrasound (US) imaging, and clinical symptoms of cirrhosis: I, normal (n = 17); II, only biochemical abnormality (n = 15); III, altered hepatic morphologic characteristics (n = 10); IV, compensated liver cirrhosis (n = 3); and V, decompensated liver cirrhosis (n = 0). We compared the area under the receiver operating characteristic curve (AUROC) data for TE, 2D SWE, the APRI, and the FIB-4 score. A combined assessment of the serologic markers and US elastography was performed, and the AUROCs of the combinations were compared.

RESULTS

Forty-five patients were included in the study (median age, 16.0 years; range, 3-35 years). Transient elastography, 2D SWE, and APRI were comparable in distinguishing the clinical categories (AUROC, 0.799-0.928). The FIB-4 score showed lower diagnostic value in distinguishing clinical category I from the other categories (AUROC, 0.647). Combining the serologic markers and US elastography significantly increased the AUROC value of the FIB-4 score (with TE and 2D SWE, P = .01 and .02).

CONCLUSIONS

Transient elastography and 2D SWE showed excellent diagnostic accuracy for differentiating the clinical categories of hepatic involvement. The APRI showed better diagnostic performance than the FIB-4 score. The assessment of hepatic manifestations in WD can be improved by combining US elastography with serologic indices.

A novel gross deletion and breakpoint junction sequence analysis of ATP7B in a Chinese family with Wilson disease using next‑generation sequencing and Sanger sequencing

Wilson disease (WD) is a rare autosomal recessive genetic disorder that causes abnormal copper metabolism, resulting in pathological accumulation of copper in the liver, brain and other organs. Mutations in the ATPase copper transporter 7B (ATP7B) gene, which encodes a membrane P-type adenosine triphosphatase, have been identified as being responsible for WD. The present study analyzed clinical data and collected DNA samples from a pediatric patient with WD and her healthy parents. Mutation screening for ATP7B was performed using direct sequencing, multiplex ligation-dependent probe amplification(MLPA), next-generation sequencing (NGS) and Sanger sequencing of the breakpoint junction sequence. The patient (age, 2.7 years) presented with early-onset hepatic disease. The present study identified compound heterozygous mutations of ATP7B, including a heterozygous mutation (p.Arg1,041Trp) and a novel heterozygous gross deletion of a 57,771 bp fragment (chr13: 52490972-52548742) (GRCh37) from partial exon2- exon21 to external ATP7B sequence (15.833bp) in the patient. Analysis of the family members of the patient showed that the missense mutation and the gross deletion mutation were inherited from her mother and father, respectively. Microhomology and inverted repeat sequences, which may mediate the deletion mutation, were identified through sequence analysis on both sides of the breakpoints of this deletion. The present study provided additional information on the genotypic spectrum of the ATP7B gene, particularly with regard to early onset hepatic disease, as observed in the present patient with WD. The identification of the precise breakpoint junction sequence warrants further investigation of DNA break and recombination mechanisms. In detecting precise deletions, the NGS associated with Sanger sequencing of breakpoint junction sequence have been found to have more advantages than MLPA.

Anterior segment optical coherence tomography (AS-OCT) as a new method of detecting copper deposits forming the Kayser-Fleischer ring in patients with Wilson disease

PURPOSE

Kayser-Fleischer ring pathognomonic for Wilson disease (WD) is formed of corneal copper deposits present predominantly within the anterior chamber angle at the Schwalbe's line. The slit-lamp assessment commonly used as a standard of care cannot detect them early enough, as the angle view is obscured by the corneal limbus. The aim of the research was to evaluate the anterior segment optical coherence tomography (AS-OCT), as objective diagnostic assessment of copper deposits forming KF ring in patients with WD.

METHODS

Twenty-nine subjects (17 women) and twenty-nine controls (14 women) were enrolled and underwent slit lamp and AS-OCT assessment.

RESULTS

Kayser-Fleischer ring was not detected - either with a slit lamp or with AS-OCT - in any of the controls. Fifteen subjects presenting without KF ring at a slit-lamp examination were found to have a KF ring when examined with AS-OCT (p < 0.001), which confirms improved accuracy of AS-OCT, as compared to the slit-lamp examination.

CONCLUSION

Our results support AS-OCT as a diagnostic procedure to offer better objectivity and accuracy as compared to a slit-lamp examination, both at the diagnostic stage and when monitoring changes in KF ring during medical therapy to assess its efficacy and patient compliance.

Neurologic Wilson disease: case series on a diagnostic and therapeutic emergency

Wilson disease is a rare genetic disease causing pathologic deposition of copper in the liver, brain, cornea, kidney, and cardiac muscles. Presented are two cases of neurologic Wilson disease with progressive movement disorder and Kayser-Fleischer rings with low serum copper, low ceruloplasmin, and increased 24-hour urine copper against a background of normal transaminases. Cranial imaging revealed symmetric basal ganglia hyperintensities in T2/FLAIR. More often than not, these cases go unnoticed and misdiagnosed because of its rarity and varied presentation. Extensive workup is necessary to confirm the diagnosis. As for management, the earlier the intervention is initiated, the better prognosis would be for recovery. There are several treatment options which should be tailored to every patient with neurologic Wilson disease. Neurologic Wilson disease is considered as a copper toxicity; immediate diagnostic evaluation and early treatment initiation is a must.

A case report and focused literature review of d-penicillamine and severe neutropenia: A serious toxicity from a seldom-used drug

Prescribing d-penicillamine for Wilson's disease must be accompanied by vigilant monitoring, including a complete blood cell count with differential. For most, this should occur once or twice weekly during the first month of therapy and during periods of dose escalation, then every two weeks for six additional months, then monthly.

Long-term evaluation of urinary copper excretion and non-caeruloplasmin associated copper in Wilson disease patients under medical treatment

OBJECTIVE

Urinary copper excretion rates and non-caeruloplasmin associated copper concentrations are increased in patients with Wilson disease. However, there is little literature describing the monitoring of these parameters over the long term.

METHODS

This is a monocentric retrospective study including data collected between 2003 and 2015 from 321 patients with Wilson disease by chart review. The patients were under therapy with D-penicillamine, trientine, or zinc. 24-h urinary copper excretion rates, non-caeruloplasmin associated copper, and total serum copper concentrations were determined at the start of therapy, as well as 6, 12, 18, 24, 36, and ≥ 60 months after the start of therapy. For patients taking chelating agents, all parameters were measured while under continued therapy, as well as after a 48-h dose interruption. A mathematical formula to predict 24-h urinary copper excretion rates under different therapies was established.

RESULTS

In all treatment groups, urinary copper excretion rates decreased over time, but the inter-individual variation of the results was high. Non-caeruloplasmin associated copper concentrations tended to decline over time, but with a higher variation of results than that observed for urinary copper excretion rates.

CONCLUSION

Due to their variability, urinary copper excretion rates and serum copper concentrations are less than ideal parameters by which to monitor the benefit of a copper-reducing therapy. Urinary copper excretion rates seem to be more suitable than non-caeruloplasmin associated copper concentrations for this purpose.

Imaging Kayser-Fleischer Ring in Wilson Disease Using In Vivo Confocal Microscopy

PURPOSE

This study analyzes images of Kayser-Fleischer (K-F) rings in patients with Wilson disease (WD) using in vivo confocal microscopy (IVCM) and explores whether IVCM can be a useful clinical tool in facilitating the diagnosis and characterization of K-F rings.

METHODS

One hundred four eyes of 52 patients with WD and K-F rings (K-F group) and 52 normal eyes of 52 age- and gender-matched control subjects (control group) were enrolled in the study. Both K-F and control groups consisted of 29 male patients and 23 female patients. IVCM imaging was performed, and images of the peripheral Descemet membrane were analyzed.

RESULTS

All patients in K-F group showed abnormal patterns in the peripheral Descemet membrane from IVCM images. These abnormalities can be generally divided into 3 types: patchy, stripy, and spotty patterns. Each patient may have a combination of these patterns, with patchy pattern being most prevalent (100%), whereas stripy and spotty patterns are present in 30% to 40% of the K-F rings. Notably, these patterns are not correlated with other systematic symptoms of WD.

CONCLUSIONS

IVCM images can be used as an objective clinical diagnostic tool to facilitate the identification of K-F rings and the diagnosis of WD.

Chalkophores

Copper-binding metallophores, or chalkophores, play a role in microbial copper homeostasis that is analogous to that of siderophores in iron homeostasis. The best-studied chalkophores are members of the methanobactin (Mbn) family-ribosomally produced, posttranslationally modified natural products first identified as copper chelators responsible for copper uptake in methane-oxidizing bacteria. To date, Mbns have been characterized exclusively in those species, but there is genomic evidence for their production in a much wider range of bacteria. This review addresses the current state of knowledge regarding the function, biosynthesis, transport, and regulation of Mbns. While the roles of several proteins in these processes are supported by substantial genetic and biochemical evidence, key aspects of Mbn manufacture, handling, and regulation remain unclear. In addition, other natural products that have been proposed to mediate copper uptake as well as metallophores that have biologically relevant roles involving copper binding, but not copper uptake, are discussed.

Delivery of Copper-chelating Trientine (TETA) to the central nervous system by surface modified liposomes

The existence of the blood-brain barrier (BBB) complicates the treatment of many central nervous system (CNS) disorders, including the copper storage disease, Wilson's disease. Its CNS symptoms represent a serious problem, since therapeutics for Wilson's disease do not cross the BBB. One strategy to overcome this obstacle is the transfer of drugs across the BBB with colloidal carrier systems like liposomes. The aim of the present study was to encapsulate triethylenetetramine (TETA), a copper chelating agent, into surface modified liposomes and to investigate their permeation across the BBB. Liposomes were modified with cationized bovine serum albumin or penetratin, a cell penetrating peptide. Liposomes were characterized regarding size, PDI, zeta potential and encapsulation efficiency. Size was between 139.4±1.9nm to 171.1±3.5nm with PDI's below 0.2. Zeta potentials of vectorized liposomes were at least 6.9mV higher than those of standard liposomes. Cryo-TEM micrographs displayed liposomal structure, integrity and the similarity of structure and size between loaded, unloaded, vectorized and non- vectorized liposomes. In vivo experiments in rats showed an up to 16-fold higher brain uptake of TETA in vectorized liposomes compared to free TETA or TETA in non-vectorized liposomes, proving successful brain delivery using target seeking surface modifications. Tissue analysis indicated TETA concentrations in the brain being high enough to treat Wilson's disease.

Molybdenum and copper in four varieties of common bean (Phaseolus vulgaris): new data of potential utility in designing healthy diet for diabetic patients

Experimental evidence indicates that diabetic patients and individuals with impaired copper homeostasis could be at risk of molybdenum toxicity. A self-administered food frequency questionnaire revealed that in central Mexico, diabetic patients with severe complications tend to consume beans more often than individuals with less advanced disease. Four varieties of Phaseolus vulgaris were comparatively evaluated as the dietary sources of two elements; the results showed molybdenum concentration decreasing in the order peruvian > pinto > mayflower > black, whereas for copper, the order was peruvian > pinto ∼ black > mayflower. The two elements were determined in pre-soaking water, cooked legumes, and broth obtained in cooking procedure; an in vitro gut model was also applied to assess potentially bioavailable fraction of both elements in cooked beans. The results indicated that the black variety would be the healthiest bean choice for diabetic patients and individuals susceptible to Mo toxicity. Relatively low total molybdenum was found in this variety (2.9 ± 1.4 versus 4.3-10.9 μg g(-1) in other types), element availability was also low (15 % in supernatant from enzymolysis, 24.9 % in combined broth + supernatant fractions), and the molar ratio of Cu/Mo was the highest among four types (41, versus Cu/Mo <10 in peruvian, pinto, or mayflower). Considering peruvian and pinto beans, broth elimination would help to lower molybdenum intake with marginal effect on Cu/Mo molar ratio. This recommendation would be especially important for peruvian variety, which provided 1090, 803, and 197 μg day(-1) of molybdenum in raw grains, broth + supernatant, and supernatant, respectively (based on 100-g portion), exceeding the recommended daily allowance of 45 μg day(-1).

Zinc mono-therapy in pre-symptomatic Chinese children with Wilson disease: a single center, retrospective study

Background

There is no official consensus regarding zinc therapy in pre-symptomatic children with Wilson Disease (WD); more data is needed.

Objective

To investigate the safety and efficacy of zinc gluconate therapy for Chinese children with pre-symptomatic WD.

Methods

We retrospectively analyzed pre-symptomatic children receiving zinc gluconate in a single Chinese center specialized in pediatric hepatology. Short-term follow-up data on safety and efficacy were presented, and effects of different zinc dosages were compared.

Results

30 children (21 males) aged 2.7 to 16.8 years were followed for up to 4.4 years; 26 (87%) children had abnormal ALT at baseline. Most patients (73%) received higher than the currently recommended dose of elemental zinc. Zinc gluconate significantly reduced mean ALT (p<0.0001), AST (p<0.0001), GGT (p<0.0001) levels after 1 month, and urinary copper excretion after 6 months (p<0.0054). Mean direct bilirubin levels dropped significantly at 1 month (p = 0.0175), 3 months (p = 0.0010), and 6 months (p = 0.0036). Serum zinc levels gradually increased and reached a significantly higher level after 6 months (p<0.0026), reflecting good compliance with the therapy. Complete blood count parameters did not change throughout the analysis period. 8 children experienced mild and transient gastrointestinal side effects. The higher zinc dose did not affect treatment response and was not associated with different or increased side effects when compared to conventional zinc dose.

Conclusion

In our cohort, zinc gluconate therapy for Chinese children with pre-symptomatic WD was effective, and higher initial dose of elemental zinc had the same level of efficacy as the conventional dose.

A review of quality of life after predictive testing for and earlier identification of neurodegenerative diseases

The past decade has witnessed an explosion of evidence suggesting that many neurodegenerative diseases can be detected years, if not decades, earlier than previously thought. To date, these scientific advances have not provoked any parallel translational or clinical improvements. There is an urgency to capitalize on this momentum so earlier detection of disease can be more readily translated into improved health-related quality of life for families at risk for, or suffering with, neurodegenerative diseases. In this review, we discuss health-related quality of life (HRQOL) measurement in neurodegenerative diseases and the importance of these "patient reported outcomes" for all clinical research. Next, we address HRQOL following early identification or predictive genetic testing in some neurodegenerative diseases: Huntington disease, Alzheimer's disease, Parkinson's disease, Dementia with Lewy bodies, frontotemporal dementia, amyotrophic lateral sclerosis, prion diseases, hereditary ataxias, Dentatorubral-pallidoluysian atrophy and Wilson's disease. After a brief report of available direct-to-consumer genetic tests, we address the juxtaposition of earlier disease identification with assumed reluctance toward predictive genetic testing. Forty-one studies examining health-related outcomes following predictive genetic testing for neurodegenerative disease suggested that (a) extreme or catastrophic outcomes are rare; (b) consequences commonly include transiently increased anxiety and/or depression; (c) most participants report no regret; (d) many persons report extensive benefits to receiving genetic information; and (e) stigmatization and discrimination for genetic diseases are poorly understood and policy and laws are needed. Caution is appropriate for earlier identification of neurodegenerative diseases but findings suggest further progress is safe, feasible and likely to advance clinical care.

The overuse of serum ceruloplasmin measurement

BACKGROUND

Wilson disease is rare, found in 3 of 100,000 people (0.03%). Ceruloplasmin is often ordered to evaluate liver enzyme elevations. Because Wilson disease often presents before middle-age, the American Association for the Study of Liver Disease recommends screening patients between the ages of 3 and 55 years with liver abnormalities of uncertain cause. We evaluate guideline adherence and the clinical and economic impact of current clinical use of ceruloplasmin.

METHODS

We reviewed all ceruloplasmin measurements at a clinical laboratory that serves a large primary care network, specialty clinics, and a 600-bed tertiary referral center between January 1, 2003, and December 12, 2011.

RESULTS

Ceruloplasmin was measured 5325 times in 5023 unique patients, resulting in 8 (0.16%) new Wilson disease diagnoses. Ceruloplasmin's positive predictive value was 8.4% (95% confidence interval, 7.7-9.3) and false-positive rate was 98.1% (95% confidence interval, 96.2-99.1). A total of 1109 ceruloplasmin levels (20.8%) were ordered in the 1066 patients aged more than 55 years (none with Wilson disease). A "shotgun" approach to liver disease diagnosis was found: Ceruloplasmin was ordered on the same day as hepatitis B (81.0%), hepatitis C (76.0%), autoimmune hepatitis (75.1%), and hemochromatosis (73.1%). Of 424 positive ceruloplasmin results, 91% were not pursued further.

CONCLUSIONS

Guideline adherence restricts ceruloplasmin use to a population with a higher pre-test probability of Wilson disease: patients with chronic liver disease aged 3 to 55 years who have been tested for common causes of liver disease. The majority of the serum ceruloplasmin was measured in patients not indicated by the guidelines, resulting in poor test performance and wasted healthcare resources. Our data on ceruloplasmin use could serve as a touchstone for broader discussions on rational clinical decision making.

Gastrointestinal side effects in children with Wilson's disease treated with zinc sulphate

AIM: To investigate the side effects of a zinc sulphate therapy in a cohort of Polish pediatric patients with Wilson’s disease.

METHODS: We retrospectively analyzed a cohort of 53 pediatric patients with Wilson’s disease treated at the Children’s Memorial Health Institute in Warsaw, Poland between the years 1996 and 2011 with zinc sulphate. Patients were diagnosed with Wilson’s disease according to the scoring system of Ferenci, with 49 cases confirmed by mutation analysis. Data about the dosage scheme of zinc sulphate, side effects and efficacy and toxicity of the treatment were collected and recorded in the patient’s medical chart at each visit to the hospital.

RESULTS: Mean age of diagnosis for the entire cohort was 10 years (range, 2.5-17 years). Duration of treatment with zinc sulfate was 83.3 wk (range, 8-344 wk). Side effects, all of gastrointestinal origin, were observed in 21 patients (40% - 9 males and 12 females), irrespective of the duration of therapy. Thirteen out of 21 patients were over the age of 10 years. The most common ATP7B mutation was p.H1069Q. Esophagogastroduodenoscopy, performed in 7 patients (33.3%) suffering from persistent and severe abdominal pain, revealed gastrointestinal ulcerations or erosions with negative Helicobacter pylori tests in all subjects investigated. The above mentioned 7 patients were treated with proton pump inhibitors. Three of those experienced resolution of symptoms, whereas proton-pump inhibitors failed to alleviate symptoms of the remaining four children and conversion of therapy to D-penicillamine was needed.

CONCLUSION: Zinc sulphate appears to cause significant gastrointestinal side effects, which children on therapy for Wilson’s disease should be closely monitored for.

Long-term effects of a combination of D-penicillamine and zinc salts in the treatment of Wilson's disease in children

The aim of this study was to investigate the effectiveness of a high-dose zinc sulfate and low-dose D-penicillamine combination in the treatment of pediatric Wilson's disease (WD). A retropective chart review of 65 patients with WD was conducted. These patients received D-penicillamine (8-10 mg/kg/day) and zinc sulfate as the primary treatment. The pediatric dose of elemental zinc is 68-85 mg/day until 6 years of age, 85-136 mg/day until 8 years of age, 136-170 mg/day until 10 years of age and then 170 mg/day, in 3 divided doses 1 h before meals. After clinical and biochemical improvement or stabilization, zinc sulfate alone was administered as the maintenance therapy. Under treatment, the majority of patients (89.2%) had a favourable outcome and 3 patients succumbed due to poor therapy compliance. No penicillamine-induced neurological deterioration was noted and side-effects were observed in <11% of patients over the entire follow-up period. Benefical results on the liver and neurological symptoms were reported following extremely long-term treatment with a combination of low-dose D-penicillamine and high-dose zinc sulfate. Therefore, this regimen is an effective and safe treatment for children with WD.

Copper imbalances in ruminants and humans: unexpected common ground

Ruminants are more vulnerable to copper deficiency than humans because rumen sulfide generation lowers copper availability from forage, increasing the risk of conditions such as swayback in lambs. Molybdenum-rich pastures promote thiomolybdate (TM) synthesis and formation of unabsorbable Cu-TM complexes, turning risk to clinical reality (hypocuprosis). Selection pressures created ruminant species with tolerance of deficiency but vulnerability to copper toxicity in alien environments, such as specific pathogen-free units. By contrast, cases of copper imbalance in humans seemed confined to rare genetic aberrations of copper metabolism. Recent descriptions of human swayback and the exploratory use of TM for the treatment of Wilson's disease, tumor growth, inflammatory diseases, and Alzheimer's disease have created unexpected common ground. The incidence of pre-hemolytic copper poisoning in specific pathogen-free lambs was reduced by an infection with Mycobacterium avium that left them more responsive to treatment with TM but vulnerable to long-term copper depletion. Copper requirements in ruminants and humans may need an extra allowance for the "copper cost" of immunity to infection. Residual cuproenzyme inhibition in TM-treated lambs and anomalies in plasma copper composition that appeared to depend on liver copper status raise this question "can chelating capacity be harnessed without inducing copper-deficiency in ruminants or humans?" A model of equilibria between exogenous (TM) and endogenous chelators (e.g., albumin, metallothionein) is used to predict risk of exposure and hypocuprosis; although risk of natural exposure in humans is remote, vulnerability to TM-induced copper deficiency may be high. Biomarkers of TM impact are needed, and copper chaperones for inhibited cuproenzymes are prime candidates.

Metal element excretion in 24-h urine in patients with Wilson disease under treatment of D-penicillamine

Wilson disease is an inherited autosomal recessive disorder causing copper accumulation and consequent toxicity. D-Penicillamine, a potent metal chelator, is an important therapy for Wilson disease. To investigate the changes of metal elements under the treatment of D-penicillamine, we determined the levels of Cu, Zn, Mg, Ca, Fe, Se, Mn, Pb, Hg, Cd, As, Tl, and Al by ICP-MS in 24-h urine of 115 Wilson disease patients who had received treatment with D: -penicillamine for 1 month to 22 years at maintenance doses, as well as 115 age-matched, healthy controls. The levels of Cu, Mg, Ca, Zn, Hg, Pb, Tl, Cd, and Mn in the 24-h urine of the cases were significantly higher than those of the controls (P < 0.05), and the observed increases in the levels of Mg, Ca, and Zn were directly correlated with the treatment duration with Pearson Correlation Coefficient (R) of 0.356 (Mg), 0.329 (Ca), and 0.313 (Zn), respectively (P < 0.05). On the other hand, the levels of Al and As in the 24-h urine were lower than those of the controls (P < 0.05) and were negatively correlated with the treatment time with R of -0.337 (Al) and -0.398 (As), respectively, (P < 0.05). Thus, this study indicates that the levels of metal elements may be altered in patients with Wilson disease under the treatment of D-penicillamine.

Behavioural and psychiatric disorders in paediatric Wilson's disease

An 11-year-old boy was treated since 6-years-old with methylphenidate for combined attention deficit and hyperactivity disorder. At age nine his behaviour had worsened and he started to have phobias. One year later persistent hypertransaminasemia was found. Physical examination showed a dysdiadocokinesia. Laboratory investigation revealed a low caeruloplasmin and augmented basal urinary copper with a positive postpenicillamine test. Liver biopsy showed high liver copper (853 µg/g) and brain MRI was normal. D-penicillamine and zinc acetate were started without side effects. ATP7B gene mutation was confirmed after treatment initiation.

Mapping brain metals to evaluate therapies for neurodegenerative disease

The brain is rich in metals and has a high metabolic rate, making it acutely vulnerable to the toxic effects of endogenously produced free radicals. The abundant metals, iron and copper, transfer single electrons as they cycle between their reduced (Fe(2+) , Cu(1+) ) and oxidized (Fe(3+) , Cu(2+) ) states making them powerful catalysts of reactive oxygen species (ROS) production. Even redox inert zinc, if present in excess, can trigger ROS production indirectly by altering mitochondrial function. While metal chelators seem to improve the clinical outcome of several neurodegenerative diseases, their mechanisms of action remain obscure and the effects of long-term use are largely unknown. Most chelators are not specific to a single metal and could alter the distribution of multiple metals in the brain, leading to unexpected consequences over the long-term. We show here how X-ray fluorescence will be a valuable tool to examine the effect of chelators on the distribution and amount of metals in the brain.

Moyamoya disease as a possible cause of neurological impairment following liver transplantation for Wilson's disease

In Wilson's disease, liver transplantation can constitute the only option for patients presenting with fulminant hepatic failure or decompensated liver disease unresponsive to drug therapy. We report the case of a 29-year-old woman receiving a liver transplant for end-stage Wilson's disease who developed neurological complications after transplantation. After an accurate evaluation of possible differential causes of neurological complications developing as the result of liver transplantation, moyamoya disease was diagnosed. Moyamoya disease is a rare cerebrovascular disease of unknown etiology. However, data exist supporting a possible role for some immunosuppressive regimens in determining the peculiar vascular alterations observed in moyamoya disease. To the best of our knowledge, the association with post-transplantation state for Wilson's disease has not been previously described.

Trace elements status in diabetes mellitus type 2: possible role of the interaction between molybdenum and copper in the progress of typical complications

It is well established that both, the deficiency and possible overload of mineral micronutrients have adverse health effects. It is also generally accepted that non-essential xenobiotics contribute to oxidative damage, which is considered one of the principal factors in diabetes and its complications. The purpose of this work was to gain an insight on the global role of metal/metalloids in the progress of diabetes mellitus type 2. In such approach, aluminum, vanadium, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, selenium, molybdenum, mercury, cadmium and lead were determined by inductively coupled plasma-mass spectrometry (ICP-MS) in serum and urine of 76 diabetic patients (age 52 ± 8 years, 5-16 years of DM2, 52 subjects with slight-to-moderate complications and 24 with severe complications). A series of anthropometric and clinical parameters usually evaluated in the follow-up of patients were assessed by standard methods. Statistical analysis (unpaired t-test, analysis of correlation and principal component analysis) was then carried out in search of possible relationships existing among metals/metalloids and these parameters. The results obtained suggest that antagonistic interaction between molybdenum and copper might be involved in the progress of diabetes complications.

Clinical and molecular characterization of Wilson's disease in China: identification of 14 novel mutations

BACKGROUND

Wilson's disease (WND) is a rare autosomal recessive disorder. Here we have evaluated 62 WND cases (58 probands) from the Chinese Han population to expand our knowledge of ATP7B mutations and to more completely characterize WND in China.

METHODS

the coding and promoter regions of the ATP7B gene were analyzed by direct sequencing in 62 Chinese patients (58 probands) with WND (male, n = 37; female, n = 25; age range, 2 ~ 61 years old).

RESULTS

neurologic manifestations were associated with older age at diagnosis (p < 0.0001) and longer diagnostic delay (p < 0.0001). Age at diagnosis was also correlated with urinary copper concentration (r = 0.58, p < 0.001). Forty different mutations, including 14 novel mutations, were identified in these patients. Common mutations included p.Arg778Leu (31.9%) and p.Pro992Leu (11.2%). Homozygous p.Arg778Leu and nonsense mutation/frameshift mutations were more often associated with primary hepatic manifestations (p = 0.0286 and p = 0.0383, respectively) and higher alanine transaminase levels at diagnosis (p = 0.0361 and p = 0.0047, respectively). Nonsense mutation/frameshift mutations were also associated with lower serum ceruloplasmin (p = 0.0065).

CONCLUSIONS

we identified 14 novel mutations and found that the spectrum of mutations of ATP7B in China is quite distinct from that of Western countries. The mutation type plays a role in predicting clinical manifestations. Genetic testing is a valuable tool to detect WND in young children, especially in patients younger than 8 years old. Four exons (8, 12, 13, and 16) and two mutations (p.Arg778Leu, p.Pro992Leu) should be considered high priority for cost-effective testing in China.

Oral complications associated with D-penicillamine treatment for Wilson disease: a clinicopathologic report

BACKGROUND

Wilson disease (WD) is a hereditary disease inhibiting copper release from the liver. Multi-organ manifestations involve the liver, nervous system, kidneys, eyes, heart, and skin. Elastic fiber damage is a complication of the most frequently used medication in the treatment of WD D-penicillamine (D-PCA). These changes have very rarely been described in the oral cavity. The article describes oral complications associated with WD and its treatment by D-PCA.

METHODS

Clinical, radiographic, and microscopic evaluation was done on two WD female patients (aged 28 and 53), treated by D-PCA, with clinical and pathological evidence for oral drug-related complications.

RESULTS

The lesions included multiple small red papules of the lips, gingival enlargement, early onset periodontitis, and repeated oral candidiasis. Biopsies of oral mucosa (gingiva, buccal) exhibited in one case granulomatous inflammation, and in both cases, thick irregular clumps of tortuous, red-staining abnormal elastic fibers. The red lip papules resemble elastosis perforans serpiginosa (EPS). Similar lesions have been described in the skin, but never before in association with oral or perioral tissue. In addition to the oral lesions, one of the patients developed general intolerance to the drug and was switched to trientine hydrochloride.

CONCLUSIONS

WD patients and others treated by D-PCA may develop oral and perioral complications, in some cases exhibiting features of damaged elastic fibers in the mucosa and periodontal apparatus. It is possible that this damage may be one of the factors responsible for poor periodontal health in WD patients. Recognition of the lesions can lead to replacement of the affecting therapeutic agent.

Copper inhibits P2Y(2)-dependent Ca(2+) signaling through the effects on thapsigargin-sensitive Ca(2+) stores in HTC hepatoma cells

Purinergic P2Y(2) G-protein coupled receptors play a key role in the regulation of hepatic Ca(2+) signaling by extracellular ATP. The concentration of copper in serum is about 20muM. Since copper accumulates in the liver in certain disease states, the purpose of these studies was to assess the effects of copper on P2Y(2) receptors in a model liver cell line. Exposure to a P2Y(2) agonist UTP increased [Ca(2+)](i) by stimulating Ca(2+) release from thapsigargin-sensitive Ca(2+) stores. Pretreatment of HTC cells for several minutes with copper did not affect cell viability, but potently inhibited increases in [Ca(2+)](i) evoked by UTP and thapsigargin. During this pretreatment, copper was not transported into the cytosol, and inhibited P2Y(2) receptors in a concentration-dependent manner with the IC(50) of about 15muM. These results suggest that copper inhibits P2Y(2) receptors through the effects on thapsigargin-sensitive Ca(2+) stores by acting from an extracellular side. Further experiments indicated that these effect of copper may lead to inhibition of regulatory volume decrease (RVD) evoked by hypotonic solution. Thus, copper may contribute to defective regulation of purinergic signaling and liver cell volume in diseases associated with the increased serum copper concentration.

Wilson's disease: long-term follow-up of a cohort of 24 patients treated with D-penicillamine

BACKGROUND AND STUDY AIMS

Detailed data on long-term effectiveness of various drug therapies in Wilson's disease (WD) are lacking. Therefore, we retrospectively reviewed our patient cohort treated with D-penicillamine.

PATIENTS AND METHODS

This study reports on the clinical presentation, the diagnostic evaluation, and the disease course in 24 WD patients treated long-term (15+/-12 years, between 1969 and 2009) with D-penicillamine.

RESULTS

The overall survival in our cohort was 91.6%. Twenty-two of 24 patients had liver disease at presentation, 17 of 24 patients (71%) had cirrhosis, 11 of whom had complications of cirrhosis. Six of 11 of these patients showed hepatological improvement (five of six) or stabilization (one of six), three of 11 were transplanted, one of 11 died, one of 11 discontinued follow-up. In the six of 17 cirrhotic patients without complications, improvement (four of six) or stabilization (two of six) occurred. Of all other patients (seven of 24), five of seven showed improvement (three of five) or stabilization (two of five), hepatological deterioration occurred only in one patient due to poor therapy compliance and one of seven discontinued follow-up. Neuropsychiatric symptoms were present in 13 of 24 at presentation and resolved in one of 13, decreased in seven of 13, stabilized in four of 13 and worsened in one of 13 patients (due to poor compliance). In general, we observed a favorable hepatological and neurological evolution with D-penicillamine.

CONCLUSION

Despite the presence of liver disease or neuropsychiatric symptoms at baseline in all but one of the patients, we report beneficial results on liver and neurological disease after very long-term treatment with D-penicillamine, thereby adding to its reputation as 'first-line' therapy in WD.

Wilson’s disease

Wilson’s disease is an autosomal-recessive disorder caused by mutation in the ATP7B gene. Absent or reduced function of ATP7B protein leads to decreased hepatocellular excretion of copper into bile. Subsequent copper accumulation, first in the liver but ultimately in the brain and other tissues, produces different clinical manifestations such as hepatic, neurological, hematological, ophthalmological, and psychiatric problems. Diagnosis is based on clinical suspicion, parameters of copper metabolism, ophthalmic examination (Kayser-Fleischer rings) and a liver biopsy. Genetic studies are of limited use. Early diagnosis and initiation of therapy with chelators and therapeutic plasma exchange therapy are essential for prognosis. Liver transplantation corrects the underlying pathophysiology and can be lifesaving in fulminant hepatic failure. Screening of siblings and 1st degree relatives of the patients is also important.

Wilson disease: Histopathological correlations with treatment on follow-up liver biopsies

AIM: To investigate the progression of hepatic histopathology in serial liver biopsies from Wilson disease (WD) patients.

METHODS: We report a group of 12 WD patients treated with zinc and/or penicillamine who underwent multiple follow-up liver biopsies. Demographic, clinical and laboratory data were gathered and all patients underwent an initial biopsy and at least one repeat biopsy.

RESULTS: Time to repeat biopsy ranged from 2 to 12 years. Six patients (non-progressors) showed stable hepatic histology or improvement. In one case, we observed improvement of fibrosis from stage 2 to 0. Six patients (progressors) had worsening of fibrosis. There was no significant correlation between the histological findings and serum aminotransferases or copper metabolism parameters. The hepatic copper concentration reached normal levels in only two patients: one from the non-progressors and one from the progressors group. The estimated rate of progression of hepatic fibrosis in the entire group was 0 units per year in the time frame between the first and the second liver biopsy (4 years), and 0.25 between the second and the third (3 years). In the progressors group, the rate of progression of liver fibrosis was estimated at 0.11 fibrosis units per year between the first and second biopsy and, 0.6 fibrosis units between the second and third biopsy.

CONCLUSION: The inability of clinical tools to detect fibrosis progression in WD suggests that a liver biopsy with hepatic copper quantification every 3 years should be considered.

Copper and zinc in the serum, urine, and hair of patients with Wilson's disease treated with penicillamine and zinc

The purpose of this study was to determine the different levels of copper and zinc in the serum, urine, and scalp hair of patients with Wilson's disease receiving different, currently accepted methods of treatment to reduce the copper load (penicillamine-group 1, n = 8; zinc-group 2, n = 8; penicillamine+zinc-group 3, n = 8). Blood, urine, and hair samples were collected from the patients. All three treatments resulted in a significant decrease of the serum copper levels. Significantly increased levels of zinc in the serum were detected in the patients in groups 2 and 3 (19.1 and 18.8 micromol/l, respectively; p < 0.05). Copper excretion in the urine significantly increased during its administration to groups 1 and 3 (11.5 and 7.94 micromol/24 h respectively; p < 0.001) due to the effect of penicillamine. The administration of zinc as monotherapy (group 2) or in combination with penicillamine (group 3) led to an increase of its excretion (25.3 and 22.4 micromol/24 h, respectively; p < 0.01). Only an insignificant rise of the copper content in the hair was found in all three groups of patients. The content of zinc in the hair did not differ significantly in any of the groups in comparison with the control group.

Reduced expression of ATP7B affected by Wilson disease-causing mutations is rescued by pharmacological folding chaperones 4-phenylbutyrate and curcumin

Wilson disease (WD) is an autosomal recessive copper overload disorder of the liver and basal ganglia. WD is caused by mutations in the gene encoding ATP7B, a protein localized to the trans-Golgi network that primarily facilitates hepatic copper excretion. Current treatment comprises reduction of circulating copper by zinc supplementation or copper chelation. Despite treatment, a significant number of patients have neurological deterioration. The aim of this study was to investigate the possibility that defects arising from some WD mutations are ameliorated by drug treatment aimed at improvement of protein folding and restoration of protein function. This necessitated systematic characterization of the molecular consequences of distinct ATP7B missense mutations associated with WD. With the exception of p.S1363F, all mutations tested (p.G85V, p.R778L, p.H1069Q, p.C1104F, p.V1262F, p.G1343V, and p.S1363F) resulted in reduced ATP7B protein expression, whereas messenger RNA abundance was unaffected. Retention of mutant ATP7B in the endoplasmic reticulum, increased protein expression, and normalization of localization after culturing cells at 30 degrees C, and homology modeling suggested that these proteins were misfolded. Four distinct mutations exhibited residual copper export capacity, whereas other mutations resulted in complete disruption of copper export by ATP7B. Treatment with pharmacological chaperones 4-phenylbutyrate (4-PBA) and curcumin, a clinically approved compound, partially restored protein expression of most ATP7B mutants.

CONCLUSION

These findings might enable novel treatment strategies in WD by directly enhancing the protein expression of mutant ATP7B with residual copper export activity. 1795.).

Systematic review: clinical efficacy of chelator agents and zinc in the initial treatment of Wilson disease

BACKGROUND

No consensus is available on the optimal initial treatment in Wilson disease.

AIM

To assess systematically the available literature of treatment in newly presenting patients with a presymptomatic, hepatic or neurological presentation of Wilson disease.

METHODS

A systematic literature search of the MEDLINE, EMBASE and COCHRANE databases was performed. Original studies on clinical efficacy of D-penicillamine, trientine, tetrathiomolybdate or zinc monotherapy as initial treatment in Wilson disease were included. A descriptive analysis of the relevant published data was performed.

RESULTS

One randomized trial and 12 observational studies met the inclusion criteria. These studies were quite heterogeneous and generally of low validity. Nevertheless, according to currently available data, patients with hepatic presentation of Wilson disease are probably most effectively treated by D-penicillamine. Zinc seems to be preferred above d-penicillamine for treatment of presymptomatic and neurological patients, as in these subgroups, the tolerance profile is in favour of zinc, while no obvious differences in clinical efficacy could be observed.

CONCLUSIONS

There is lack of high-quality evidence to estimate the relative treatment effects of the available drugs in Wilson disease. Therefore, multicentre prospective randomized controlled comparative trials are necessary.