Bone status and fractures in 85 adults with Wilson's disease

Wilson's Disease

Wilson's disease (WD) can present with liver disease, neurological deficits, and psychiatric disorders. Results of genetic prevalence studies suggest that WD might be much more common than previously estimated. Early recognition of WD remains challenging because it is a great imitator and requires a high index of suspicion for correct and timely diagnosis. Early diagnosis of WD is crucial to ensure that patients can be started on adequate treatment. In association with other clinical and biochemical tests, liver biopsy results and molecular genetic testing can also be used for diagnosing WD. Medical therapy is effective for most patients; liver transplant can rescue those with acute liver failure or those with advanced liver disease who fail to respond to or discontinue medical therapy. Although novel therapies, such as gene therapy, are on the horizon, screening and prevention of delayed diagnosis remains paramount.

Metabolic bone disease heralding the diagnosis of Wilson's disease

We report a short-statured, young man in his 20s presenting with bilateral cataract, recurrent kidney stones, history of refractory rickets and bone deformity. He had been consuming calcium and vitamin D supplements and had been operated for cataract and renal stone disease, prior to reporting in our clinic without any significant laboratory or clinical improvement. The patient was diagnosed as having Fanconi's syndrome attributable to Wilson's disease. This patient highlights that in case of resistant rickets, a high index of suspicion must be invoked for Wilson's disease. Timely recognition of this entity results in prompt ministrations and prevention of disability.

COMMD1, a multi-potent intracellular protein involved in copper homeostasis, protein trafficking, inflammation, and cancer

Copper is a trace element indispensable for life, but at the same time it is implicated in reactive oxygen species formation. Several inherited copper storage diseases are described of which Wilson disease (copper overload, mutations in ATP7B gene) and Menkes disease (copper deficiency, mutations in ATP7A gene) are the most prominent ones. After the discovery in 2002 of a novel gene product (i.e. COMMD1) involved in hepatic copper handling in Bedlington terriers, studies on the mechanism of action of COMMD1 revealed numerous non-copper related functions. Effects on hepatic copper handling are likely mediated via interactions with ATP7B. In addition, COMMD1 has many more interacting partners which guide their routing to either the plasma membrane or, often in an ubiquitination-dependent fashion, trigger their proteolysis via the S26 proteasome. By stimulating NF-κB ubiquitination, COMMD1 dampens an inflammatory reaction. Finally, targeting COMMD1 function can be a novel approach in the treatment of tumors.

An Overview of the Molecular Mechanisms Contributing to Musculoskeletal Disorders in Chronic Liver Disease: Osteoporosis, Sarcopenia, and Osteoporotic Sarcopenia

The prevalence of osteoporosis and sarcopenia is significantly higher in patients with liver disease than in those without liver disease and osteoporosis and sarcopenia negatively influence morbidity and mortality in liver disease, yet these musculoskeletal disorders are frequently overlooked in clinical practice for patients with chronic liver disease. The objective of this review is to provide a comprehensive understanding of the molecular mechanisms of musculoskeletal disorders accompanying the pathogenesis of liver disease. The increased bone resorption through the receptor activator of nuclear factor kappa (RANK)-RANK ligand (RANKL)-osteoprotegerin (OPG) system and upregulation of inflammatory cytokines and decreased bone formation through increased bilirubin and sclerostin and lower insulin-like growth factor-1 are important mechanisms for osteoporosis in patients with liver disease. Sarcopenia is associated with insulin resistance and obesity in non-alcoholic fatty liver disease, whereas hyperammonemia, low amount of branched chain amino acids, and hypogonadism contributes to sarcopenia in liver cirrhosis. The bidirectional crosstalk between muscle and bone through myostatin, irisin, β-aminoisobutyric acid (BAIBA), osteocalcin, as well as the activation of the RANK and the Wnt/β-catenin pathways are associated with osteosarcopenia. The increased understandings for these musculoskeletal disorders would be contributes to the development of effective therapies targeting the pathophysiological mechanism involved.

Long-Term Accumulation of Metals in the Skeleton as Related to Osteoporotic Derangements

The concentrations of metals in the environment are still not within the recommended limits as set by the regulatory authorities in various countries because of human activities. They can enter the food chain and bioaccumulate in soft and hard tissues/organs, often with a long half-life of the metal in the body. Metal exposure has a negative impact on bone health and may result in osteoporosis and increased fracture risk depending on concentration and duration of metal exposure and metal species. Bones are a long-term repository for lead and some other metals, and may approximately contain 90% of the total body burden in birds and mammals. The present review focuses on the most common metals found in contaminated areas (mercury, cadmium, lead, nickel, chromium, iron, and aluminum) and their effects on bone tissue, considering the possibility of the long-term bone accumulation, and also some differences that might exist between different age groups in the whole population.

Renal Tubular Function, Bone Health and Body Composition in Wilson's Disease: A Cross-Sectional Study from India

There is limited literature from India with regard to the prevalence and magnitude of renal tubular and bone manifestations in Wilson's disease (WD). Thus, we studied the prevalence of renal tubular acidosis among Indian patients with WD and also evaluated bone health and body composition in them. It was a cross-sectional study conducted at a south Indian tertiary care center. Twenty-five consecutive patients with WD aged more than 12 years attending the hepatology and neurology departments and 50 age, sex and BMI-matched controls were recruited. After clinical assessment, they underwent biochemical testing to assess renal tubular dysfunction. Bone mineral density (BMD) and body composition were assessed using a dual energy X-ray absorptiometry (DXA) scanner. Fifty-six percent (14/25) of patients with WD had renal tubular acidosis (RTA). Of them, 24% were diagnosed to have distal RTA. RTA was more common in hepatic WD patients who had prolonged duration of illness. Patients with WD had significantly lower BMD as compared to control subjects (p < 0.05). Low BMI, low IGF-1 and a shorter duration of therapy were key determinants of low bone mass in them (p < 0.05). Patients with WD had significantly more body fat (p = 0.01) and lower lean muscle mass (p = 0.03) when compared to age, sex and BMI-matched controls. In conclusion, renal tubular acidosis was common in patients with Wilson's disease. These patients had a lower bone mineral density, higher body fat percentage and lower lean muscle mass as compared to controls.

Hepatic Osteodystrophy-Molecular Mechanisms Proposed to Favor Its Development

Almost all patients with chronic liver diseases (CLD) show altered bone metabolism. Depending on the etiology, this manifests in a severe osteoporosis in up to 75% of the affected patients. Due to high prevalence, the generic term hepatic osteodystrophy (HOD) evolved, describing altered bone metabolism, decreased bone mineral density, and deterioration of bone structure in patients with CLD. Once developed, HOD is difficult to treat and increases the risk of fragility fractures. Existing fractures affect the quality of life and, more importantly, long-term prognosis of these patients, which presents with increased mortality. Thus, special care is required to support the healing process. However, for early diagnosis (reduce fracture risk) and development of adequate treatment strategies (support healing of existing fractures), it is essential to understand the underlying mechanisms that link disturbed liver function with this bone phenotype. In the present review, we summarize proposed molecular mechanisms favoring the development of HOD and compromising the healing of associated fractures, including alterations in vitamin D metabolism and action, disbalances in transforming growth factor beta (TGF-β) and bone morphogenetic protein (BMP) signaling with histone deacetylases (HDACs) as secondary regulators, as well as alterations in the receptor activator of nuclear factor kappa B ligand (RANKL)–osteoprotegerin (OPG) system mediated by sclerostin. Based on these mechanisms, we give an overview on the limitations of early diagnosis of HOD with established serum markers.

Clinical manifestations of Wilson disease in organs other than the liver and brain

Wilson disease (WD) is an inherited genetic disorder that is caused by copper metabolism disturbances with main hepatic, neurological, and psychiatric presentation. Deposits of copper accumulate in different organs and may cause a broad range of clinical manifestations. Patients with WD may present with ophthalmological symptoms, or renal, cardiac and osteoarticular involvement. The most common ophthalmological sign as a result of copper accumulation is the Kayser-Fleischer corneal ring, whereas sunflower cataracts are observed rarely. Retinal degeneration, present in WD patients, may serve as a marker of neurodegeneration. Osteoarticular involvement is quite common and includes osteopenia, osteoporosis and arthropathy, which may lead to bone fractures and joint problems mainly affecting knees and wrists. Renal disturbances include tubular dysfunction and renal calculi. A recent cardiac study has shown a higher risk of atrial fibrillation and heart failure in WD patients than in non-WD patients. Autonomic system dysfunction is also observed, but involvement is subclinical in most cases. Another manifestation of WD concerns endocrine system disturbances, which can lead to recurrent abortions, infertility, growth disruption, and parathyroid failure. However, it is possible to become pregnant for females with mild WD symptoms and for those who are compliant with therapy. Hematologic disturbances are frequent and may include acute hemolytic anemia, leucopenia, anemia and low platelet count. Other observed symptoms include lipomas and characteristic of WD skin changes like hyperpigmentation of the legs, xerosis or azure lunulae of the nails. In this paper, we present some of the less common, but nevertheless, important manifestations of WD.

Serum copper levels are associated with bone mineral density and total fracture

Background

Both copper deficiency and overexposure have been associated with adverse health effects. Evidence linking copper to bone mineral density (BMD) and total fracture, however, is limited.

Methods

This nationally representative cross-sectional study enrolled participants from the National Health and Nutrition Examination Survey (2011–2014) in the United States. Using unadjusted and multivariate adjusted logistic regression analyses and a two-piecewise linear regression model with a smoothing function, we evaluated the associations between serum copper levels, bone mineral density and total fracture in 722 participants.

Results

The study sample (n = 722, mean age: 56.47 ± 11.55 y) represented a population of which 47.2% were men; 43.91% were non-Hispanic white, 18.84% non-Hispanic black and 13.71% Mexican American; 25.9% had total fracture. In the multivariate logistic regression analysis, individuals in the lowest category (<98.5 μg/dL) of serum copper concentration had 0.049 g/cm² lower total femur BMD and 0.045 g/cm² lower femoral neck BMD than those in the second concentration category (98.5–114 μg/dL). Individuals in the highest category (≥134 μg/dL) of serum copper concentration had an approximately 4-fold increase in the risk of total fracture than those in the second concentration category. There were no significant associations between per 10 μg/dL increases in serum copper levels and total fracture in multivariate logistic regression analysis after multivariate adjustment (all p > 0.05). However, a differential association between serum copper levels and total fractures between men and women was observed (odds ratio = 1.81, 95% confidence interval 1.08–3.03, p = 0.026 for men and odds ratio = 1.07, 95% confidence interval 0.86–1.32, p = 0.552 for women).

Conclusion

Moderate serum copper levels are critically important for bone health. Lower serum copper levels are significantly associated with decreased BMD in the total femur and femoral neck. Higher serum copper levels are significantly associated with increased total fracture, especially in men.

The Translational Potential of this Article

The impact of serum copper concentrations on bone mineral density and total fracture can provide insights into clinical application of copper-containing supplements and biomaterials.

Bone health in patients with inborn errors of metabolism

Inborn errors of metabolism encompass a wide spectrum of disorders, frequently affecting bone. The most important metabolic disorders that primarily influence calcium or phosphate balance, resulting in skeletal pathology, are hypophosphatemic rickets and hypophosphatasia. Conditions involving bone marrow or affecting skeletal growth and development are mainly the lysosomal storage disorders, in particular the mucopolysaccharidoses. In these disorders skeletal abnormalities are often the presenting symptom and early recognition and intervention improves outcome in many of these diseases. Many disorders of intermediary metabolism may impact bone health as well, resulting in higher frequencies of osteopenia and osteoporosis. In these conditions factors contributing to the reduced bone mineralization can be the disorder itself, the strict dietary treatment, reduced physical activity or sunlight exposure and/or early ovarian failure. Awareness of these primary or secondary bone problems amongst physicians treating patients with inborn errors of metabolism is of importance for optimization bone health and recognition of skeletal complications.

Osteoporosis and bone mineral density in patients with Wilson's disease: a systematic review and meta-analysis

This systematic review aims to assess the occurrence and risks of osteopenia and osteoporosis in patientswith Wilson's disease (WD). A literature search was conducted utilizing EMBASE and MEDLINE frominception through April 2017. Studies assessing the occurrence or risk of osteopenia and/or osteoporosis inWD patients were included. Effect estimates from the individual study were extracted and combined usingrandom-effect, generic inverse variance method of DerSimonian and Laird. Of 754 studies, four studies with283 WD patients met the eligibility criteria and were included in the data analysis. The pooled prevalencerates of osteopenia and osteoporosis in WD patients were 36.5% (95% confidence interval [CI]: 14.8%-65.7%) and 27.7% (95%CI: 8.6%-60.9%), respectively. When meta-analysis was limited only to adults, the estimated prevalence rates of osteopenia, osteoporosis, and vertebral fracture were 50.0% (95%CI: 42.0%-58.0%), 17.6% (95%CI: 6.7%-38.6%) and 8.01% (95%CI: 4.05%-15.2%), respectively. Meta-regressionshowed significant impacts of age (negative correlation; P=0.002) and male status (positive correlation;P < 0.001) on the prevalence of osteoporosis. The data on risks of osteopenia and osteoporosis in WDpatients were limited. We suggests that there are potential associations of WD with osteopenia and/orosteoporosis. Also, young age and male status are correlated with the higher prevalence of osteoporosis inWD patients.

Wilson Disease

PURPOSE OF REVIEW

This article reviews the clinical features of Wilson disease, focusing on the neurologic and psychiatric abnormalities, and addresses the diagnostic workup and treatment approaches to managing the disease.

RECENT FINDINGS

The list of known mutations causing Wilson disease continues to grow, but advances in genetic testing may soon make it feasible to routinely perform genetic testing on individuals suspected of having Wilson disease.

SUMMARY

Wilson disease is a rare genetic disorder with protean manifestations that should be considered in the differential diagnosis of any individual presenting with unexplained neurologic, psychiatric, or hepatic dysfunction. Appropriate diagnostic testing should be expeditiously performed and treatment promptly initiated and maintained since failure to diagnose and treat Wilson disease will result in progressive and ultimately irreversible damage to the neurologic and other systems.

Epidemiology, diagnosis, and treatment of Wilson's disease

Wilson's disease (WD) is an autosomal recessive disease caused by a mutation of the ATP7B gene, resulting in abnormal copper metabolism. The major clinical features of WD include liver disease, neurological disorders, K-F rings, and osteoporosis. The prevalence of WD in China is higher than that in Western countries. Early diagnosis and lifelong treatment will lead to better outcomes. Drugs such as sodium dimercaptosuccinate (Na-DMPS), Zn, and Gandou Decoction can be used to treat WD. Some studies have shown that the combination of traditional Chinese medicine and Western medicine is the best approach to treating WD. In order to identify better treatments, this article describes the specific clinical symptoms of Wilson's disease, its diagnosis, and treatment options.

Pathological Fracture of Femoral Neck Leading to a Diagnosis of Wilson's Disease: A Case Report and Review of Literature

Wilson's disease (WD) is a rare inherited disorder of copper metabolism. It chiefly has hepatic, neurological and ophthalmic manifestations. Although osteoporosis, rickets and early arthritis are common features of WD, they are under-recognized. Musculoskeletal manifestations very rarely lead to diagnosis of the disease. Here we present a case of a 12-year-old girl who presented with a 3-month-old pathological fracture of neck of femur. WD was diagnosed on investigating the cause of the pathological fracture, which was managed by performing a conventional McMurray's intertrochanteric osteotomy. At 6 months follow up, fracture had united and patient was able to ambulate with support. WD can be a rare cause of pathological fracture. A high index of suspicion must be maintained in patients of pathological fracture presenting with associated neuropsychiatric or hepatic manifestations.

Other organ involvement and clinical aspects of Wilson disease

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

Bone demineralisation in a large cohort of Wilson disease patients

AIMS AND BACKGROUND

We compared the bone mineral density (BMD) of adult Wilson disease (WD) patients (n = 148), with an age- and gender-matched healthy control population (n = 148). Within the WD cohort, correlations of BMD with WD disease parameters, lab results, type of treatment and known osteoporosis risk factors were analysed.

METHODS

Hip and lumbar spine absolute BMD and T-score were measured by dual-energy X-ray absorptiometry. Osteoporosis and osteopenia were defined as a T-score ≤ -2.5, and between -1 and -2.5, respectively.

RESULTS

There were significantly more subjects with abnormal T-scores in the WD population (58.8%) than in the control population (45.3%) (χ(2) = 6.65, df = 2, p = 0.036), as there were 50.0% osteopenic and 8.8% osteoporotic WD patients, vs. 41.2% and 4.1%, respectively, in the controls. Especially L2-L4 spine BMD measurements (BMD and T-scores) differed significantly between the WD population and matched controls. L2-L4 spine BMD for WD patients was on average 0.054 g/cm(2) (5.1%) lower than in matched normal controls (0.995 ± 0.156 vs 1.050 ± 0.135; p = 0.002). We found no significant correlation between BMD values and any of the WD disease parameters (e.g. the severity of liver disease), lab results, type of treatment or known osteoporosis risk factors. Duration of D-penicillamine treatment was negatively correlated with femoral BMD value, but in a clinically irrelevant manner, compared to age and gender. Importantly, BMD remained significantly lower in WD patients (n = 89) vs. controls after excluding WD patients with cirrhosis (p = 0.009).

CONCLUSIONS

Our study suggests that WD is intrinsically associated with bone demineralisation.