Wilson disease: Clinical manifestations, diagnosis, and treatment

Copper homeostasis and cuproptosis in health and disease

Copper is a vital trace element in human physiology, essential for the synthesis of numerous crucial metabolic enzymes and facilitation of various biological processes. Regulation of copper levels within a narrow range is imperative for maintaining metabolic homeostasis. Numerous studies have demonstrated the significant roles of copper homeostasis and cuproptosis in health and disease pathogenesis. However, a comprehensive and up-to-date systematic review in this domain remains absent. This review aims to consolidate recent advancements in understanding the roles of cuproptosis and copper homeostasis in health and disease, focusing on the underlying mechanisms and potential therapeutic interventions. Dysregulation of copper homeostasis, manifesting as either copper excess or deficiency, is implicated in the etiology of various diseases. Cuproptosis, a recently identified form of cell death, is characterized by intracellular copper overload. This phenomenon mediates a diverse array of evolutionary processes in organisms, spanning from health to disease, and is implicated in genetic disorders, liver diseases, neurodegenerative disorders, and various cancers. This review provides a comprehensive summary of the pathogenic mechanisms underlying cuproptosis and copper homeostasis, along with associated targeted therapeutic agents. Furthermore, it explores future research directions with the potential to yield significant advancements in disease treatment, health management, and disease prevention.

Total Copper and Labile Bound Copper Fraction as a Selective and Sensitive Tool in the Evaluation of Wilson Disease

BACKGROUND

A dual filtration-based method for determination of serum labile bound copper (LBC) and LBC fraction (LBC/total copper) was developed. Reduced total copper, elevated LBC, and elevated LBC fraction have been reported in Wilson disease (WD).

METHODS

To evaluate the diagnostic performance of these markers, samples were obtained from 21 WD treatment-naïve (WD-TN, no WD treatment or <28 days of treatment) patients, 46 WD standard-of-care-treated (WD-SOC) patients, along with 246 patients representing other potential disorders of copper status. These were then compared to 213 reference interval population patients.

RESULTS

Receiver operating characteristic curves for the reference population vs WD-TN yielded areas under the curve for total copper, LBC, and LBC fraction, of 0.99, 0.81, and 0.98, respectively. Using Youden cutoffs, sensitivity/specificity for WD-TN was 95%/97% for total copper, 71%/85% for LBC, and 95%/94% for LBC fraction. LBC values, but not total copper and LBC fraction, differed substantially between WD-TN and WD-SOC cohorts.We propose a dual model wherein total copper and LBC fraction results must agree to be classified as a "positive" or "negative" result for WD. This correctly classified 19/21 WD-TN patients as positive, and 194/213 reference interval patients as negative. The remaining "indeterminate" patients (representing approximately 9% of the reference and the WD-TN populations) exhibited conflicting total copper and LBC fraction results. When indeterminate results are excluded, this model exhibited apparent 100% sensitivity/specificity.

CONCLUSIONS

Agreement of total serum copper and LBC fraction classification may constitute an effective "rule-in" and "rule-out" assessment for WD-TN patients.

"Because it is a rare disease…it needs to be brought to attention that there are things out of the norm": a qualitative study of patient and physician experiences of Wilson disease diagnosis and management in the US

BACKGROUND

Wilson disease (WD) is a genetic disorder of copper metabolism that leads to copper accumulation in various organs, primarily the liver and brain, resulting in heterogenous hepatic, neurologic, and psychiatric symptoms. Diagnosis can occur at any age, requiring lifelong treatment, which can involve liver transplantation. This qualitative study aims to understand the wider patient and physician experience of the diagnosis and management of WD in the US.

METHODS

Primary data were collected from 1:1 semi structured interviews with US-based patients and physicians and thematically analyzed with NVivo.

RESULTS

Twelve WD patients and 7 specialist WD physicians (hepatologists and neurologists) were interviewed. Analysis of the interviews revealed 18 themes, which were organized into 5 overarching categories: (1) Diagnosis journey, (2) Multidisciplinary approach, (3) Medication, (4) The role of insurance, and (5) Education, awareness, and support. Patients who presented with psychiatric or neurological symptoms reported longer diagnostic journeys (range 1 to 16 years) than those presenting with hepatic symptoms or through genetic screening (range 2 weeks to 3 years). All were also affected by geographical proximity to WD specialists and access to comprehensive insurance. Exploratory testing was often burdensome for patients, but receipt of a definitive diagnosis led to relief for some. Physicians emphasized the importance of multidisciplinary teams beyond hepatology, neurology, and psychiatry and recommended a combination of chelation, zinc, and a low-copper diet; however, only half the patients in this sample were on a chelator, and some struggled to access prescription zinc due to insurance issues. Caregivers often advocated for and supported adolescents with their medication and dietary regimen. Patients and physicians recommended more education and awareness for the healthcare community.

CONCLUSIONS

WD requires the coordination of care and medication among several specialists due to its complex nature, but many patients do not have access to multiple specialties due to geographical or insurance barriers. Because some patients cannot be treated in Centers of Excellence, easy access to reliable and up-to-date information is important to empower physicians, patients, and their caregivers in managing the condition, along with general community outreach programs.

Mitochondrial dysfunction reactivates α-fetoprotein expression that drives copper-dependent immunosuppression in mitochondrial disease models

Signaling circuits crucial to systemic physiology are widespread, yet uncovering their molecular underpinnings remains a barrier to understanding the etiology of many metabolic disorders. Here, we identified a copper-linked signaling circuit activated by disruption of mitochondrial function in the murine liver or heart that resulted in atrophy of the spleen and thymus and caused a peripheral white blood cell deficiency. We demonstrated that the leukopenia was caused by α-fetoprotein, which required copper and the cell surface receptor CCR5 to promote white blood cell death. We further showed that α-fetoprotein expression was upregulated in several cell types upon inhibition of oxidative phosphorylation. Collectively, our data argue that α-fetoprotein may be secreted by bioenergetically stressed tissue to suppress the immune system, an effect that may explain the recurrent or chronic infections that are observed in a subset of mitochondrial diseases or in other disorders with secondary mitochondrial dysfunction.

Accumulation of molybdenum in major organs following repeated oral administration of bis-choline tetrathiomolybdate in the Sprague Dawley rat

Molybdenum is an essential dietary trace element required for several critical enzyme systems. High intake is associated with toxicity in ruminants and animal studies. The proposed therapeutic use of molybdenum based drugs poses a potential risk for accumulation through chronic administration of therapeutic doses of this element. The current experiment was designed to study the effect of daily dosing of a molybdenum compound, bis-choline tetrathiomolybdate (TTM), in Sprague Dawley rats using laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-ToF-MS), and two dosing levels of TTM for up to 3-months. To investigate if molybdenum accumulation was associated with tissue toxicity, histopathology, haematology and clinical biochemistry markers of toxicity were incorporated into the study design. There were no behavioural signs of toxicity to the rats, and no clinical or anatomic pathology associated with treatment. The current data did show a progressive accumulation of molybdenum within the adrenal gland, kidneys, liver, spleen, brain and testes. While this was not associated with tissue toxicity within the three-month study design, greater exposure over a longer period of time has potential for adverse pathophysiological cellular function. Tissue toxicity, as a result of local excessive accumulation of molybdenum over time has clear implications for the therapeutic use of molybdenum in humans and demands sensitive monitoring of tissue molybdenum levels to avoid toxicity. The current study highlights the shortcomings of conventional biomonitoring approaches to detect molybdenum accumulation with the goal of avoiding molybdenum associated toxicity.

Wilson's Disease: An Analysis of Health Care Use and Cost Burden of Commercially Insured Adults in the United States

The economic and health care use burdens of Wilson’s disease (WD) are unknown. In this study, we aimed to quantify this health care resource use and economic burden. We performed a retrospective case‐control analysis of individuals in the Truven Health MarketScan Commercial Claims database (2007‐2017). Using propensity scores, 424 WD cases were matched 1:1 to chronic liver disease (CLD) controls without WD. Total and service‐specific parameters, expressed in monthly averages, were quantified for the 6‐month pre‐WD diagnosis versus the 12‐month period after diagnosis. Wilcoxon signed‐rank tests and McNemar tests were used to examine incremental differences in burden between cases and controls. Adjusted multivariable generalized linear regression models were used to compare health care burdens. Relative to the 6‐month pre‐WD diagnosis, the 12 months after diagnosis had more claims per patient (2.87 vs. 3.35; P < 0.0001) and increased per patient health care costs (US $2,089 vs. US $3,887; P < 0.0001). WD cases incurred US $1,908 more in total unadjusted costs compared to controls in the 12‐month postindex date monthly averages. The increase in claims was primarily due to outpatient visits (1.62 vs. 1.82) and pharmaceutical claims (1.11 vs. 1.37). Cases also had higher health care costs for inpatient admissions (US $559 vs. US $1,264), outpatient visits (US $770 vs. US $1,037), and pharmaceutical claims (US $686 vs. US $1,489). Conclusion: WD is associated with significant health care cost and use burdens driven by increased inpatient admissions, outpatient visits, and pharmaceutical claims.

Recommendations for the medical work-up of first episode psychosis, including specific relevance to Indigenous Australians: A narrative review

AIMS

To collate existing literature for busy practicing psychiatrists about the medical work-up for first-episode psychosis (FEP). Therefore, (a) to review current guidelines for the medical work-up of first episode psychosis. (b) To examine whether any specific recommendations for Indigenous Australians exist. (c) To produce an easy reference table of evidence based investigations.

METHOD

A multi-part narrative review process was undertaken. Step 1 "Source identification and summary": identified key existing national and international guidelines and expert opinions related to the medical work-up of FEP and summarised these suggestions. Step 2 "Exploration of each investigation": examined each of the identified investigations for its importance. Step 3 "Relevance to Indigenous Australians": reviewed any particular relevance to the Indigenous Australian population. Step 4 "Clinician guide": involved presenting recommended investigations in a simple table.

RESULTS

Multiple guidelines were identified. There was clear consensus for many aspects. However, there were also differences in the approach for some investigations. Clinical reasoning for the proposed investigations was commonly absent. There were limited specific recommendations for Indigenous Australians. Evidence and importance was explored for each investigation and auseful table for the practicing psychiatrist was constructed. Investigations were stratified into those considered to be "universal," "low yield," or "unecessary."

CONCLUSION

A narrative review of multiple guidelines relating to the medical work-up of FEP identified many similarities and some differences to their approach. Little additional information exists for the Indigenous Australian context. A clinician friendly worksheet for everyday use may be helpful to busy clinicians.

How to approach a patient with parkinsonism - red flags for atypical parkinsonism

Parkinsonism is a clinical syndrome defined by bradykinesia plus rigidity or tremor. Though most commonly encountered in the setting of idiopathic Parkinson's disease, a number of neurodegenerative, structural, metabolic and toxic neurological disorders can result in parkinsonism. Accurately diagnosing the underlying cause of parkinsonism is of both therapeutic and prognostic relevance, especially as we enter the era of disease-modifying treatment trials for neurodegenerative disorders. Being aware of the wide array of potential causes of parkinsonism is of paramount importance for clinicians. In this chapter, we present a pragmatic clinical approach to patients with parkinsonism, specifically focusing on 'red flags', which should alert one to consider diagnoses other than idiopathic Parkinson's disease.

The six metal binding domains in human copper transporter, ATP7B: molecular biophysics and disease-causing mutations

Wilson Disease (WD) is a hereditary genetic disorder, which coincides with a dysfunctional copper (Cu) metabolism caused by mutations in ATP7B, a membrane-bound P1B-type ATPase responsible for Cu export from hepatic cells. The N-terminal part (~ 600 residues) of the multi-domain 1400-residue ATP7B constitutes six metal binding domains (MBDs), each of which can bind a copper ion, interact with other ATP7B domains as well as with different proteins. Although the ATP7B's MBDs have been investigated in vitro and in vivo intensively, it remains unclear how these domains modulate overall structure, dynamics, stability and function of ATP7B. The presence of six MBDs is unique to mammalian ATP7B homologs, and many WD causing missense mutations are found in these domains. Here, we have summarized previously reported in vitro biophysical data on the MBDs of ATP7B and WD point mutations located in these domains. Besides the demonstration of where the research field stands today, this review showcasts the need for further biophysical investigation about the roles of MBDs in ATP7B function. Molecular mechanisms of ATP7B are important not only in the development of new WD treatment but also for other aspects of human physiology where Cu transport plays a role.