Genotype-phenotype correlation in Italian children with Wilson's disease

Phenotypic and genetic characterization of children with Wilson Disease from Northeast China

BACKGROUND

Wilson disease (WD) is an autosomal recessive inherited disease caused by ATP7B variants and characterized by copper metabolism defects. However, children with WD are often asymptomatic, making the clinical diagnosis difficult. Therefore, more accurate methods are required for clinical diagnosis. The objective of this study was to highlight the phenotypic and genetic characteristics of children with WD in northeast China.

METHODS

We retrospectively analyzed the clinical data and gene sequencing results of 65 children with WD from January 1, 2014, to December 31, 2022, at the Shengjing Hospital of China Medical University. All data refer to the time of diagnosis before treatment.

RESULTS

The median age at diagnosis was 5 years (range 1.2-15 years). In 50 cases (50/65, 76.9%) patients, routine physical examinations revealed only abnormal liver function. However, they had a significantly negative (p < 0.05) Kayser-Fleischer ring (KF). Children with acute liver failure had significantly increased 24 h urinary copper excretion (p < 0.05). We detected 46 genetic variants of ATP7B, including seven novel variants. The most frequent variant was p.R778L with an allele frequency of 38.7%. Phenotype-genotype correlation analysis suggested that p.R778L was significantly associated with lower serum ceruloplasmin levels and higher zinc levels (p < 0.05). The loss-of-function (LOF) variant was associated with significantly lower albumin levels (p < 0.05).

CONCLUSION

Most children with WD are asymptomatic, which makes early diagnosis of WD difficult. Therefore, clinical and laboratory characteristics as well as genetic testing are essential. p.R778L is the most frequent variant of ATP7B in China and may play an important role in lowering serum ceruloplasmin levels.

Clinical characteristics and prognosis of early diagnosed Wilson's disease: A large cohort study

BACKGROUND AND AIMS

Few studies have focused on the outcomes of Wilson's disease (WD) diagnosed before age of 5 years. This study aimed to summarize the clinical features of early diagnosed WD and analyse treatment outcomes and the risk factors associated with treatment failure.

METHODS

A total of 139 children confirmed with WD before 5 years were enrolled in this study. Only patients with follow-up over 1 year were analysed with Kaplan-Meier survival analysis. The composite outcomes included death, progression to liver failure or acute hepatitis, development of renal or neurological symptoms and persistent elevation of alanine aminotransferase (ALT). The treatment failure was defined as occurrence of at least one of above outcomes.

RESULTS

Among 139 WD patients at diagnosis, two (1.4%) WD patients presented with symptomatic liver disease, whereas 137 (98.6%) were phenotypically asymptomatic, including 135 with elevated ALT and 2 with normal liver function. Median serum ceruloplasmin (Cp) was 3.1 mg/dL, and urinary copper excretion was 87.4 μg/24-h. There were 71 variants identified in the the copper-transporting ATPase beta gene, and 29 were loss of function (LOF). 51 patients with LOF variant were younger at diagnosis and had lower Cp than 88 patients without LOF. Among 93 patients with over 1 year of follow-up, 19 (20.4%) received zinc monotherapy, and 74 (79.6%) received a zinc/D-penicillamine combination therapy. 14 (15.1%) patients underwent treatment failure, and its occurrence was associated with poor compliance (p < .01).

CONCLUSIONS

Cp is a reliable biomarker for early diagnosis, and zinc monotherapy is an effective treatment for WD during early childhood. Good treatment compliance is critical to achieve a favourable outcome.

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

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

Clinical spectrum and genotype-phenotype associations in Finnish patients with Wilson's disease

Genotype-phenotype correlation data covering all ages of Wilson's disease onset in Caucasian patients are limited. We therefore analyzed genotype-phenotype correlations in a retrospective cohort of Finnish patients. Six homozygous (HoZ) and 11 compound heterozygous (CoHZ) patients were included. There were no differences in the presence/absence of hepatic, neurological, psychiatric or any symptoms at diagnosis (p > 0.30 for all) between HoZ and CoHZ patients, but HoZ patients had an earlier age of diagnosis (median 6.7 versus 34.5; p = 0.003). Severe liver affliction was almost exclusively associated with the p.H1069Q variant. Patients with p.H1069Q had a later mean age of diagnosis (30.2 ± 11.6 vs. 8.7 ± 4.9 years; p < 0.001) compared to those without. There were no differences in the presence/absence of hepatic, neurological, psychiatric or any symptoms at diagnosis between p.H1069Q-positive and p.H1069Q-negative patients (p > 0.54 for all). These results suggest that population-specific factors may partly explain the high clinical variability of Wilson's disease.

ATP7B Genotype and Chronic Liver Disease Treatment Outcomes in Wilson Disease: Worse Survival With Loss-of-Function Variants

BACKGROUND AND AIMS

Although a good genotype-phenotype correlation has not been established in Wilson disease (WD), patients with loss-of-function (LOF) ATP7B variants demonstrate different clinical and biochemical characteristics. We aim to describe long-term treatment outcomes in the chronic liver disease (CLD) phenotype and evaluate an association with LOF variants.

METHODS

This was a single-center retrospective review of WD patients with at least 1 variant in ATP7B. Demographic, biochemical, genetic, and clinical parameters were obtained. The composite clinical endpoint of liver transplantation or death was used for probands with CLD phenotype on chelators.

RESULTS

Of 117 patients with hepatic WD: 71 had CLD, 27 had fulminant hepatic failure requiring urgent liver transplantation, and 19 were diagnosed through family screening. Median age at diagnosis was 13.1 (interquartile range, 9.7-17.6) years. In total, 91 variants in ATP7B were identified in the study population. At least 1 LOF variant was present in 60 (51.3%) patients. During median follow-up of 10.7 (interquartile range, 6.7-18.9) years, 10 (14.1%) of the probands with CLD reached the composite endpoint. There was a worse transplant-free survival for patients prescribed chelation therapy in patients with at least 1 LOF variant (P = .03).

CONCLUSIONS

Patients with WD and CLD phenotype on chelators, who have at least 1 LOF variant in ATP7B, have a worse prognosis during long-term follow up. This subgroup of patients requires close monitoring for signs of progressive liver disease. Sequencing of ATP7B may be used in the diagnosis of WD, and in addition, it may provide useful prognostic information for patients with hepatic WD.

Wilson disease diagnosed incidentally by targeted gene panel sequencing in a Korean boy with severe obesity

Wilson disease (WD) is a relatively common genetic hepatic disease in children and is characterized by excessive copper accumulation, predominantly in the liver and brain. It is an autosomal recessive disease caused by an ATP7B mutation that causes brain degeneration and is potentially fatal if diagnosed late or untreated. In the early phase of WD, its initial presentation may include mild hepatic involvement. WD may be overlooked as a cause of liver disease due to severe obesity but should not be excluded from differential diagnosis. We report a case of WD with severe obesity and fatty liver diagnosed in the early phase by targeted gene panel sequencing and review the endocrine problems associated with WD. Early suspicion of WD is important for good prognosis.

Epidemiology, clinical features, and mortality rate of Wilson disease in Moroccan children: A pediatric case series

BACKGROUND AND STUDY AIMS

Wilson's disease is an autosomal recessive disorder, that affects copper metabolism, leading to copper accumulation in the liver, nervous system, and cornea. Data are lacking on the epidemiology, the clinical and laboratory characteristics, treatment, and survival of Wilson's disease in Morocco. The aim of this study was to examine these features and the cause of death in a Moroccan pediatric population.

PATIENTS AND METHODS

The study was carried out at the University Hospital Center of Marrakesh, Morocco; 46 children were diagnosed with Wilson's disease from 2008 to 2019. The diagnosis was based on low serum ceruloplasmin, increased urinary copper concentrations, the presence of Kayser-Fleischer rings, a family history of Wilson's disease, and a Leipzig score of ≥ 4.

RESULTS

A total of 42 patients were referred to the center for hepatic or neurological manifestations; four patients were asymptomatic. Consanguineous marriage was found in 67.4% of the cases. The mean duration of illness (42 patients) was 4.9 ± 3.9 years. Kayser-Fleischer rings were found in 60.9% of 46 patients. Of the 42 symptomatic patients: 28 of 30 (93.3%) patients had low serum ceruloplasmin (<0.2 g/L), and 24 h urinary copper >100 μg/day was found in 34 of 35 (97.1%) cases. The treatment was established with D-penicillamine for 43 of the 46 patients, with zinc acetate for one patient and with zinc sulfate in for one patient, while one patient was not treated. D-penicillamine was discontinued in nine patients because of adverse effects such as thrombocytopenia, neurological deterioration, pancytopenia, severe vomiting and severe hypersensitivity. In total 28 patients were clinically and biologically stabilized, two patients experienced vision loss, and 16 patients died (38%). The main cause of death was diagnosis made at an advanced stage of disease and stopping treatment.

CONCLUSION

Wilson's disease is a rare condition associated with treatement efficacy, but late diagnosis and stopping treatment can lead to a high mortality rate.

Assessment of the diagnostic value of serum ceruloplasmin for Wilson's disease in children

Background

Serum ceruloplasmin is one of the major diagnostic parameters for Wilson’s disease (WD). Age and gender difference of serum ceruloplasmin remain controversy. This study aims to assess diagnostic value of serum ceruloplasmin level for WD in children up to age of 15 years.

Methods

Serum ceruloplasmin levels were measured in 317 WD patients, 21 heterozygotes, 372 healthy control children and 154 non-WD patients with other liver diseases. Receiver operating characteristic (ROC) curve was used to determine the diagnostic accuracy of serum ceruloplasmin for WD in children.

Results

Among healthy controls, serum ceruloplasmin level was slightly low in the infants younger than 6 months, and then maintained from 26 to 33 mg/dl after age of 6 months. A total of 8.1% of healthy children had levels of serum ceruloplasmin < 20 mg/dL. Serum ceruloplasmin level was 5.7 ± 4.7 mg/dl in WD patients, and 25.6 ± 5.9 mg/dl in heterozygous carriers. Only 1.9% of WD patients had serum ceruloplasmin levels > 20 mg/dL. Serum ceruloplasmin levels had gender difference, being higher in healthy boys than healthy girls, and higher in asymptomatic WD boys than asymptomatic WD girls (p < 0.01, p < 0.05). Serum ceruloplasmin levels also presented genotypic difference. WD patients with R778L homozygotes exhibited lower levels of serum ceruloplasmin than the patients without R778L (p < 0.05). The ROC curve revealed that serum ceruloplasmin level, at a cutoff value of 16.8 mg/dL, had the highest AUC value (0.990) with a sensitivity of 95.9% and a specificity of 93.6%.

Conclusions

Serum ceruloplasmin is one of sensitive diagnostic biomarkers for WD in children. Gender and genotypic difference of serum ceruloplasmin level should be considered. The cutoff value of serum ceruloplasmin level < 16.8 mg/dL may provide the highest accuracy for diagnosis of WD in children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02186-0.

Acute liver failure with hemolytic anemia in children with Wilson’s disease: Genotype-phenotype correlations?

BACKGROUND

Wilson’s disease (WD) is a rare autosomal recessive inherited disorder of copper metabolism. Acute liver failure (ALF) and hemolytic anemia represent the most severe presentation of WD in children. No clear genotype-phenotype correlations exist in WD. Protein-truncating nonsense, frame-shift, or splice-site variants may be associated with more severe disease. In contrast, missense variants may be associated with late-onset, less severe disease, and more neurological manifestations. Recently, a gene variant (HSD17B13:TA, rs72613567) with a possible hepatic protective role against toxins was associated with a less severe hepatic phenotype in WD.

AIM

To analyze the possible genotype-phenotype correlations in children with WD presented with ALF and non-immune hemolytic anemia.

METHODS

The medical records of children with WD diagnosed and treated in our hospital from January 2006 to December 2020 were retrospectively analyzed. The clinical manifestations (ALF with non-immune hemolytic anemia or other less severe forms), laboratory parameters, copper metabolism, ATP7B variants, and the HSD17B13:TA (rs72613567) variant were reviewed to analyze the possible genotype-phenotype correlations.

RESULTS

We analyzed the data of 51 patients with WD, 26 females (50.98%), with the mean age at the diagnosis of 12.36 ± 3.74 years. ALF and Coombs-negative hemolytic anemia was present in 8 children (15.67%), all adolescent girls. The Kayser-Fleisher ring was present in 9 children (17.65%). The most frequent variants of the ATP7B gene were p.His1069Gln (c.3207A>G) in 38.24% of all alleles, p.Gly1341Asp (c.4021G>A) in 26.47%, p.Trp939Cys (c.2817G>T) in 9.80%, and p.Lys844Ter (c.2530A>T) in 4.90%. In ALF with hemolytic anemia, p.Trp939Cys (c.2817G>T) and p.Lys844Ter (c.2530A>T) variants were more frequent than in other less severe forms, in which p.His1069Gln (c.3207A>G) was more frequent. p.Gly1341Asp (c.4021G>A) has a similar frequency in all hepatic forms. For 33 of the patients, the HSD17B13 genotype was evaluated. The overall HSD17B13:TA allele frequency was 24.24%. Its frequency was higher in patients with less severe liver disease (26.92%) than those with ALF and hemolytic anemia (14.28%).

CONCLUSION

It remains challenging to prove a genotype-phenotype correlation in WD patients. In children with ALF and hemolytic anemia, the missense variants other than p.His1069Gln (c.3207A>G) and frame-shift variants were the most frequently present in homozygous status or compound heterozygous status with site splice variants. As genetic analysis is usually time-consuming and the results are late, the importance at the onset of the ALF is questionable. If variants proved to be associated with severe forms are found in the pre-symptomatic phase of the disease, this could be essential to predict a possible severe evolution.

Infantile ATP7B-Related End-Stage Liver Disease: An Exceptional Wilson Disease Phenotype From Consecutive Generations

Wilson disease (WD) is a rare autosomal recessive disorder of copper metabolism typically presenting after 3 years of age. We describe a girl presenting with neonatal cholestasis rapidly progressing to end-stage liver disease. She presented hepatosplenomegaly, neurological impairment, Coombs-negative hemolytic anemia, central hypothyroidism. A patient-parents whole exome sequencing identified a homozygous state for ATP7B mutations causing WD in the proband (p.Gln7fs/p.His1069Gln) and her mother (p.His1069Gln/p.His1069Gln), who was then confirmed to have cirrhotic WD. A causative role of copper toxicity due to ATP7B loss of function was indicated by the presence of extrahepatic features of WD, consistent tests of copper metabolism-including a 7-fold increase in liver copper-and similarity of patient's liver gene expression profile and ultrastructure with that of WD models. This exceptionally early presentation could result from the combination of the ATP7B impairment and the intrauterine copper overload due to maternal undiagnosed WD.

ATP7B variant c.1934T > G p.Met645Arg causes Wilson disease by promoting exon 6 skipping

Wilson disease is a recessive genetic disorder caused by pathogenic loss-of-function variants in the ATP7B gene. It is characterized by disrupted copper homeostasis resulting in liver disease and/or neurological abnormalities. The variant NM_000053.3:c.1934T > G (Met645Arg) has been reported as compound heterozygous, and is highly prevalent among Wilson disease patients of Spanish descent. Accordingly, it is classified as pathogenic by leading molecular diagnostic centers. However, functional studies suggest that the amino acid change does not alter protein function, leading one ClinVar submitter to question its pathogenicity. Here, we used a minigene system and gene-edited HepG2 cells to demonstrate that c.1934T > G causes ~70% skipping of exon 6. Exon 6 skipping results in frameshift and stop-gain, leading to loss of ATP7B function. The elucidation of the mechanistic effect for this variant resolves any doubt about its pathogenicity and enables the development of genetic medicines for restoring correct splicing.

The co-occurrence of Wilson disease and X-linked agammaglobulinemia in one family highlights the promising diagnostic potential of proteolytic analysis

BACKGROUND

We report the first case of a family with co-occurrence of Wilson disease (WD), an autosomal recessive disorder of copper metabolism, and X-linked agammaglobulinemia (XLA), a primary immunodeficiency disorder (PIDD) that features marked reduction in circulating B lymphocytes and serum immunoglobulins.

METHODS AND RESULTS

Through utilization of a multiplexed biomarker peptide quantification method known as the immuno-SRM assay, we were able to simultaneously and independently identify which family members are affected with WD and which are affected with XLA using dried blood spots (DBS).

CONCLUSION

Being able to delineate multiple diagnoses using proteolytic analysis from a single DBS provides support for implementation of this methodology for clinical diagnostic use as well as large-scale population screening, such as newborn screening (NBS). This could allow for early identification and treatment of affected individuals with WD or XLA, which have been shown to reduce morbidity and decrease mortality in these two populations.

An enhanced workflow for variant interpretation in UniProtKB/Swiss-Prot improves consistency and reuse in ClinVar

Personalized genomic medicine depends on integrated analyses that combine genetic and phenotypic data from individual patients with reference knowledge of the functional and clinical significance of sequence variants. Sources of this reference knowledge include the ClinVar repository of human genetic variants, a community resource that accepts submissions from external groups, and UniProtKB/Swiss-Prot, an expert-curated resource of protein sequences and functional annotation. UniProtKB/Swiss-Prot provides knowledge on the functional impact and clinical significance of over 30 000 human protein-coding sequence variants, curated from peer-reviewed literature reports. Here we present a pilot study that lays the groundwork for the integration of curated knowledge of protein sequence variation from UniProtKB/Swiss-Prot with ClinVar. We show that existing interpretations of variant pathogenicity in UniProtKB/Swiss-Prot and ClinVar are highly concordant, with 88% of variants that are common to the two resources having interpretations of clinical significance that agree. Re-curation of a subset of UniProtKB/Swiss-Prot variants according to American College of Medical Genetics and Genomics (ACMG) guidelines using ClinGen tools further increases this level of agreement, mainly due to the reclassification of supposedly pathogenic variants as benign, based on newly available population frequency data. We have now incorporated ACMG guidelines and ClinGen tools into the UniProt Knowledgebase (UniProtKB) curation workflow and routinely submit variant data from UniProtKB/Swiss-Prot to ClinVar. These efforts will increase the usability and utilization of UniProtKB variant data and will facilitate the continuing (re-)evaluation of clinical variant interpretations as data sets and knowledge evolve.

Genetics and epigenetic factors of Wilson disease

Wilson disease (WD) is a complex condition due to copper accumulation mainly in the liver and brain. The genetic base of WD is represented by pathogenic mutations of the copper-transporting gene ATP7B with consequent lack of copper excretion through the biliary tract. ATP7B is the only gene so far identified and known to be responsible for the development of the disease. Our understanding of the disease has been evolving as functional studies have associated specific disease-causing mutations with specific copper-transporter impairments. The most frequent variant in patients of European descent is the H1069Q missense mutation and it has been associated with protein misfolding, aberrant phosphorylation of the P-domain, and altered ATP binding orientation and affinity. Conversely, there is much less understanding of the relation between the genotype and the clinical manifestations of WD. WD is characterized by a highly varied and unpredictable presentation with different combined hepatic, neurological, and psychiatric symptoms. Several studies have attempted to correlate genotype and phenotype but the most recent evidences on larger populations failed to identify a relation between genotype and clinical presentations. Given that so far also modifier genes have not shown convincing association with WD, there is growing interest to identify epigenetic mechanisms of gene expression regulation as underlying the onset and progression of WD phenotype. Evidence from animal models indicated changes in methionine metabolism regulation with possible effects on DNA methylation. Mouse models of WD have indicated transcript level changes of genes related to DNA methylation in fetal and adult livers. And finally, evidence is accumulating regarding DNA methylation changes in patients with WD. It is unexplored how ATP7B genetic mutations combine with epigenetic changes to affect the phenotype. In conclusion, WD is a genetic disease with a complex regulation of its phenotype that includes molecular genetics and epigenetic mechanisms.

Biochemical Markers for the Diagnosis and Monitoring of Wilson Disease

Wilson disease (WD) is an autosomal recessively-inherited disorder of copper metabolism and characterised by a pathological accumulation of copper. The ATP7B gene encodes for a transmembrane copper transporter essential for biliary copper excretion. Depending on time of diagnosis, severity of disease can vary widely. Almost all patients show evidence of progressive liver disease. Neurological impairments or psychiatric symptoms are common in WD patients not diagnosed during adolescence. WD is a treatable disorder, and early treatment can prevent the development of symptoms in patients diagnosed while still asymptomatic. This is why the early diagnosis of WD is crucial. The diagnosis is based on clinical symptoms, abnormal measures of copper metabolism and DNA analysis. Available treatment includes chelators and zinc salts which increase copper excretion and reduce copper uptake. In severe cases, liver transplantation is indicated and accomplishes a phenotypic correction of the hepatic gene defect. Recently, clinical development of the new copper modulating agent tetrathiomolybdate has started and direct genetic therapies are being tested in animal models. The following review focuses especially on biochemical markers and how they can be utilised in diagnosis and drug monitoring.

Wilson disease

Wilson disease (WD) is a potentially treatable, inherited disorder of copper metabolism that is characterized by the pathological accumulation of copper. WD is caused by mutations in ATP7B, which encodes a transmembrane copper-transporting ATPase, leading to impaired copper homeostasis and copper overload in the liver, brain and other organs. The clinical course of WD can vary in the type and severity of symptoms, but progressive liver disease is a common feature. Patients can also present with neurological disorders and psychiatric symptoms. WD is diagnosed using diagnostic algorithms that incorporate clinical symptoms and signs, measures of copper metabolism and DNA analysis of ATP7B. Available treatments include chelation therapy and zinc salts, which reverse copper overload by different mechanisms. Additionally, liver transplantation is indicated in selected cases. New agents, such as tetrathiomolybdate salts, are currently being investigated in clinical trials, and genetic therapies are being tested in animal models. With early diagnosis and treatment, the prognosis is good; however, an important issue is diagnosing patients before the onset of serious symptoms. Advances in screening for WD may therefore bring earlier diagnosis and improvements for patients with WD.

Biochemical and molecular characterisation of neurological Wilson disease

Background

To identify biochemical and genetic features that characterise neurological Wilson disease as a distinct disease subgroup.

Methods

Detailed biochemical profiles and genotypic characteristics of neurological (86 patients) and hepatic subgroups (233 patients) from 368 unrelated Korean families were analysed.

Results

Compared with patients in the hepatic subgroup, patients in the neurological subgroup had a later age at onset, a higher proportion with Kayser-Fleischer rings and higher serum creatinine levels, and a lower proportion with favourable outcome (62% vs 80%, P<0.016). At diagnosis, the neurological subgroup had lower serum ceruloplasmin (3.1±2.1 mg/dL vs 4.2±3.2 mg/dL, P<0.001), total copper (26.4±13.8 µg/dL vs 35.8±42.4 µg/dL, P=0.005), free copper (17.2±12.5 µg/dL vs 23.5±38.2 µg/dL, P=0.038) and urinary copper (280.9±162.9 µg/day vs 611.1±1124.2 µg/day, P<0.001) levels. Serum aspartate aminotransferase, alanine aminotransferase, gamma glutamyltransferase and total bilirubin levels, as well as prothrombin time, were also lower in the neurological subgroup. Liver cirrhosis was more common but mostly compensated in the neurological subgroup. Frameshift, nonsense or splice-site ATP7B mutations and mutations in transduction or ATP hinge domains (2.4% vs 23.1%, P=0.006) were less common in the neurological subgroup.

Conclusion

The neurological subgroup had distinct clinical, biochemical and genetic profiles. Further studies are required to identify the factors, with or without association with copper metabolism, underlying the neurological presentation for which treatment needs to be targeted to improve the clinical outcome of this subgroup.

Next generation sequencing in pediatric hepatology and liver transplantation

Next generation sequencing (NGS) has revolutionized the analysis of human genetic variations, offering a highly cost-effective way to diagnose monogenic diseases (MDs). Because nearly half of the children with chronic liver disorders have a genetic cause and approximately 20% of pediatric liver transplantations are performed in children with MDs, NGS offers the opportunity to significantly improve the diagnostic yield in this field. Among the NGS strategies, the use of targeted gene panels has proven useful to rapidly and reliably confirm a clinical suspicion, whereas the whole exome sequencing (WES) with variants filtering has been adopted to assist the diagnostic workup in unclear clinical scenarios. WES is powerful but challenging because it detects a great number of variants of unknown significance that can be misinterpreted and lead to an incorrect diagnosis. In pediatric hepatology, targeted NGS can be very valuable to discriminate neonatal/infantile cholestatic disorders, disclose genetic causes of acute liver failure, and diagnose the subtype of inborn errors of metabolism presenting with a similar phenotype (such as glycogen storage disorders, mitochondrial cytopathies, or nonalcoholic fatty liver disease). The inclusion of NGS in diagnostic processes will lead to a paradigm shift in medicine, changing our approach to the patient as well as our understanding of factors affecting genotype-phenotype match. In this review, we discuss the opportunities and the challenges offered nowadays by NGS, and we propose a novel algorithm for cholestasis of infancy adopted in our center, including targeted NGS as a pivotal tool for the diagnosis of liver-based MDs. Liver Transplantation 24 282-293 2018 AASLD.

Early Onset of Wilson Disease: Diagnostic Challenges

OBJECTIVES

The aim of the study was to analyze the clinical presentations, diagnosis, and treatment of patients ages ≤5 years with early onset Wilson disease (WD).

METHODS

Data from 143 pediatric patients with WD treated at our center between January 1996 and November 2015 were retrospectively analyzed.

RESULTS

A review of the 143 pediatric patients with WD identified 21 (10 girls, 11 boys) with first symptoms or abnormal liver function test results at age ≤5 years. The diagnosis of WD was confirmed in 8 patients younger than 5 years. At baseline the mean serum alanine aminotransferase level was 222 U/L and the mean serum aspartate aminotransferase level was 130 U/L. The mean serum ceruloplasmin concentration in 16 tested patients was <20 mg/dL. Of the 15 patients who underwent urinary copper excretion testing, 8 had levels between 40 and 100 μg/day, with only 4 having levels >100 μg/day. Liver copper quantification was >250 μg/g dry weight in 16 patients. The most common mutation was p.H1069Q, with compound heterozygosity in 5 patients and homozygosity in 9. Sixteen patients were treated with zinc salts and 5 with D-penicillamine. Both treatments were effective, with no serious side effects observed after 3 to 24 months.

CONCLUSIONS

WD can present as early as 2 years of age. Because biochemical tests may be less sensitive in very young children, diagnoses may require a combination of tests. If molecular tests are inconclusive, liver copper content should be measured.

Wilson disease: At the crossroads between genetics and epigenetics-A review of the evidence

Environmental factors, including diet, exercise, stress, and toxins, profoundly impact disease phenotypes. This review examines how Wilson disease (WD), an autosomal recessive genetic disorder, is influenced by genetic and environmental inputs. WD is caused by mutations in the copper-transporter gene ATP7B, leading to the accumulation of copper in the liver and brain, resulting in hepatic, neurological, and psychiatric symptoms. These symptoms range in severity and can first appear anytime between early childhood and old age. Over 300 disease-causing mutations in ATP7B have been identified, but attempts to link genotype to the phenotypic presentation have yielded little insight, prompting investigators to identify alternative mechanisms, such as epigenetics, to explain the highly varied clinical presentation. Further, WD is accompanied by structural and functional abnormalities in mitochondria, potentially altering the production of metabolites that are required for epigenetic regulation of gene expression. Notably, environmental exposure affects the regulation of gene expression and mitochondrial function. We present the "multi-hit" hypothesis of WD progression, which posits that the initial hit is an environmental factor that affects fetal gene expression and epigenetic mechanisms and subsequent "hits" are environmental exposures that occur in the offspring after birth. These environmental hits and subsequent changes in epigenetic regulation may impact copper accumulation and ultimately WD phenotype. Lifestyle changes, including diet, increased physical activity, stress reduction, and toxin avoidance, might influence the presentation and course of WD, and therefore may serve as potential adjunctive or replacement therapies.

Spectrum of ATP7B mutations and genotype-phenotype correlation in large-scale Chinese patients with Wilson Disease

Wilson disease (WD), an inherited disorder associated with ATP7B gene, has a wide spectrum of genotypes and phenotypes. In this study, we developed a rapid multiplex PCR-MassArray method for detecting 110 mutant alleles of interest, and used it to examine genomic DNA from 1222 patients and 110 healthy controls. In patients not found to have any mutation in the 110 selected alleles, PCR-Sanger sequencing was used to examine the ATP7B gene. We identified 88 mutations, including 9 novel mutations. Our analyses revealed p.Arg778Leu, p.Arg919Gly and p.Thr935Met showed some correlations to phenotype. The p.Arg778Leu was related to younger onset age and lower levels of ceruloplasmin (Cp) and serum copper, while p.Arg919Gly and p.Thr935Met both indicated higher Cp levels. Besides, the p.Arg919Gly was related to neurological subtype, and p.Thr935Met showed significant difference in the percentage of combined neurological and visceral subtype. Moreover, for ATP7B mutations, the more severe impact on ATP7B protein was, the younger onset age and lower Cp level presented. The feasibility of presymptomatic DNA diagnosis and predicting clinical manifestation or severity of WD would be facilitated with identified mutations and genotype-phenotype correlation precisely revealed in the study.

Update on the clinical management of Wilson's disease

Wilson's disease (WD), albeit relatively rare, is an important genetic metabolic disease because of highly effective therapies that can be lifesaving. It is a great imitator and requires a high index of suspicion for correct and timely diagnosis. Neurologic, psychiatric and hepatologic problems in WD are very nonspecific, and we discuss the most common clinical phenotypes. The diagnosis remains laboratory based, and here we review the most important challenges and pitfalls in laboratory evaluation of WD, including the emerging role of genetic testing in WD diagnosis. WD is a monogenic disorder but has very high allelic heterogeneity with >500 disease-causing mutations identified, and new insights into phenotype-genotype correlations are also reviewed. The gold standard of therapy is chelation of excessive copper, but many unmet needs exist because of possible clinical deterioration in treated patients and potential adverse effects associated with currently available chelating medications. We also review the most promising novel therapeutic approaches, including chelators targeting specific cell types, cell transplantation and gene therapy.

Pediatric liver diseases: current challenges and future perspectives

Chronic liver diseases in children represent a rising problem with significant effects on public health. In fact, several pediatric liver diseases are precursors of adult chronic hepatopathies, cirrhosis and hepatocellular carcinoma. The prevalence of liver diseases in children is unknown. In the USA, every year, 15,000 children are hospitalized for liver diseases, but these disorders continue to be under-recognized or diagnosed late. The main reason is due to the frequent absence of symptoms in the vast majority of liver diseases, especially in the early stages. In the last few decades several advances have been made in understanding the pathogenesis of liver diseases, permitting the discovery of new therapeutic targets to treat liver diseases, thus improving the natural history of these disorders. In this article we discuss the most recent advances in the understanding of the pathogenesis, diagnosis and treatment of the most frequent pediatric liver diseases.

Wilson’s disease: A review of what we have learned

Wilson’s disease (WD), which results from the defective ATP7B protein product, is characterized by impaired copper metabolism and its clinical consequences vary from an asymptomatic state to fulminant hepatic failure, chronic liver disease with or without cirrhosis, neurological, and psychiatric manifestations. A high grade of suspicion is warranted to not miss cases of WD, especially less florid cases with only mild elevation of transaminases, or isolated neuropsychiatric involvement. Screening in first and second relatives of index cases is mandatory, and treatment must commence upon establishment of diagnosis. Treatment strategies include chelators such as D-penicillamine and trientine, while zinc salts act as inductors of methallothioneins, which favor a negative copper balance and a reduction of free plasmatic copper. As an orphan disease, research is lacking in this field, especially regarding therapeutic strategies which are associated with better patient compliance and which could eventually also reverse established injury.

Prospective evaluation of the diagnostic accuracy of hepatic copper content, as determined using the entire core of a liver biopsy sample

Hepatic copper determination is an important test for the diagnosis of Wilson's disease (WD). However, the method has not been standardized, the diagnostic accuracy has not been evaluated prospectively, and the optimal cut-off value remains controversial. Accordingly, we aimed to prospectively evaluate the diagnostic accuracy of hepatic copper content, as determined using the entire core of a liver biopsy sample. Patients for whom a liver biopsy was indicated were consecutively enrolled. Hepatic copper content was determined with atomic absorption spectroscopy. All assays were performed using careful quality control by a single technician. WD diagnosis was based on WD score or its combination with clinical follow-up results. A total of 3,350 consecutive patients underwent liver biopsy. Six hundred ninety-one patients, including 178 with WD, underwent two passes of liver biopsy with hepatic copper determination. Mean hepatic content in WD patients was 770.6 ± 393.2 μg/g dry weight (wt). Sensitivity, specificity, and positive and negative predictive values of hepatic copper content for WD diagnosis in the absence of primary biliary cirrhosis (PBC) or primary sclerosing cholangitis at the cut-off value of 250 μg/g dry wt. were 94.4%, 96.8%, 91.8%, and 97.8%, respectively. The most useful cut-off value was 209 μg/g dry wt, with a sensitivity and specificity of 99.4% and 96.1%, respectively. A total of 23.3% of patients without WD and PBC had hepatic copper content >75 μg/g dry wt.

CONCLUSION

A liver biopsy sample of more than 1 mg dry wt may reliably reflect hepatic copper content and should be used for hepatic copper determination. Hepatic copper determination is a very valid procedure for the diagnosis of WD, and the most useful cut-off value is 209 μg/g dry wt.

Defective roles of ATP7B missense mutations in cellular copper tolerance and copper excretion

Wilson's disease (WD) is a hereditary disorder of copper metabolism resulting from mutations within ATP7B. Clinical investigations showed that ATP7B missense mutations cause a wide variety of symptoms in WD patients, which implies that those mutations might affect ATP7B function in a number of ways and each would have deleterious consequences on normal copper distribution and lead to WD. Nonetheless, it is still unknown about the influences of those mutations on ATP7B function of increasing copper excretion and enhancing cellular copper tolerance. Here we established the stable expression cell lines of wild-type (WT) ATP7B and its four missense mutants (R778L, R919G, T935M and P992L), tested cellular copper tolerance and copper excretion using those cell lines, and also observed cellular distribution of WT ATP7B proteins and those mutants in transiently transfected cells. We found that extrinsic expressing WT ATP7B reduced CuCl2-induced copper accumulation and enhanced cellular copper tolerance by accelerating copper excretion, which was selectively compromised by R778L and P992L mutations. Further investigation showed that R778L mutation disrupted the subcellular localization and trafficking of ATP7B proteins, whereas P992L mutation only affected the trafficking of ATP7B. This indicates that ATP7B missense mutants have distinct effects on cellular copper tolerance.

Genetic and Clinical Analysis in a Cohort of Patients with Wilson's Disease in Southwestern China

BACKGROUND AND AIMS

Wilson's disease (WD), characterized by a disorder of copper metabolism, is an inherited autosomal recessive disease caused by mutations in the ATP7B gene.

METHODS

To explore genotype-phenotype correlations in Chinese WD patients and to evaluate the frequency of the ATP7B mutations, we described 77 clinically and biochemically confirmed WD patients and detected mutations in ten WD families from southwestern China. Clinical features were presented and all the exons of the ATP7B gene were screened.

RESULTS

The appearance of Kayser-Fleischer (K-F) rings was closely related to onset age, particularly before 10 years old. For those patients with predominantly neurological symptoms, MRI was the most sensitive and preferred examination. Eight mutations of the ATP7B gene were detected including seven reported mutations (c.2302dup, c.2304delC, c.2333 G>T, c.2621 C>T, c.2755 C>G, c.2975 C>T and c.1366 G>C) and four novel mutations (c.3446 G>A, c.3767insCA, c.3406 G>A and c.3700delG). c.2333 G>T was detected in 6/20 alleles (30%), accounting for the largest proportion, which could be regarded as a mutation hotspot in this region.

CONCLUSIONS

Our study extends the mutation spectrum of ATP7B and analyzes the relationship between mutations in the ATP7B gene and clinical findings of WD.

Phenotype-genotype correlation in Wilson disease in a large Lebanese family: association of c.2299insC with hepatic and of p. Ala1003Thr with neurologic phenotype

Genotype phenotype correlations in Wilson disease (WD) are best established in homozygous patients or in compound heterozygous patients carrying the same set of mutations. We determined the clinical phenotype of patients with WD carrying the c.2298_2299insC in Exon 8 (c.2299insC) or the p. Ala1003Thr missense substitution in Exon 13 mutations in the homozygous or compound heterozygous state. We investigated 76 members of a single large Lebanese family. Their genotypes were determined, and clinical assessments were carried out for affected subjects. We also performed a literature search retrieving the phenotypes of patients carrying the same mutations of our patients in the homozygous or compound heterozygous state. There were 7 consanguineous marriages in this family and the prevalence of WD was 8.9% and of carriers of ATP7B mutation 44.7%. WD was confirmed in 9 out of 76 subjects. All 9 had the c.2299insC mutation, 5 homozygous and 4-compound heterozygous with p. Ala1003Thr. Six of our patients had hepatic, 2 had neurologic and 1 had asymptomatic phenotype. Based on our data and a literature review, clear phenotypes were reported for 38 patients worldwide carrying the c.2299insC mutation. About 53% of those have hepatic and 29% have neurologic phenotype. Furthermore, there were 10 compound heterozygous patients carrying the p. Ala1003Thr mutation. Among those, 80% having c.2299insC as the second mutation had hepatic phenotype, and all others had neurologic phenotype. We hereby report an association between the c.2299insC mutation and hepatic phenotype and between the p. Ala1003Thr mutation and neurologic phenotype.

Genotype-phenotype correlations in a mountain population community with high prevalence of Wilson's disease: genetic and clinical homogeneity

Wilson’s disease is an autosomal recessive disorder caused by more than 500 mutations in ATP7B gene presenting considerably clinical manifestations heterogeneity even in patients with a particular mutation. Previous findings suggested a potential role of additional genetic modifiers and environment factors on phenotypic expression among the affected patients. We conducted clinical and genetic investigations to perform genotype-phenotype correlation in two large families living in a socio-culturally isolated community with the highest prevalence of Wilson’s disease ever reported of 1∶1130. Sequencing of ATP7B gene in seven affected individuals and 43 family members identified a common compound heterozygous genotype, H1069Q/M769H-fs, in five symptomatic and two asymptomatic patients and detected the presence of two out of seven identified single nucleotide polymorphisms in all affected patients. Symptomatic patients had similar clinical phenotype and age at onset (18±1 years) showing dysarthria and dysphagia as common clinical features at the time of diagnosis. Moreover, all symptomatic patients presented Kayser-Fleischer rings and lack of dystonia accompanied by unfavourable clinical outcomes. Our findings add value for understanding of genotype-phenotype correlations in Wilson’s disease based on a multifamily study in an isolated population with high extent of genetic and environmental homogeneity as opposed to majority of reports. We observed an equal influence of presumed other genetic modifiers and environmental factors on clinical presentation and age at onset of Wilson’s disease in patients with a particular genotype. These data provide valuable inferences that could be applied for predicting clinical management in asymptomatic patients in such communities.

Wilson disease: what is still unclear in pediatric patients?

Since Wilson disease (WD) may not be present with evident clinical symptoms of liver injury and neurological presentation is rare in children, establishing a diagnosis is often challenging, especially in childhood. Increased transaminases can be the only abnormality found in early course of WD. In clinical practice, high suspicion is crucial for early diagnosis and timely treatment to ensure better outcomes. Conventional diagnostic criteria established for adults are commonly agreed for children but may not always be appropriate in very young age. Currently, the best therapeutic approach for each specific presentation of the disease remains controversial and there are no clear indications about how to treat pediatric WD patients with a mild liver disease.

Pathogenesis and management of Wilson disease

Hepatolenticular degeneration, commonly known as Wilson disease, is an autosomal recessive inherited disease of abnormal copper metabolism, characterized by the accumulation of copper in the body due to decreased biliary excretion of copper from hepatocytes. Wilson disease protein, ATP7B, functions in copper excretion into bile and in copper secretion to the bloodstream coupled with ceruloplasmin synthesis. Various kinds of mutations of ATP7B cause Wilson disease. Wilson disease is a rare genetic disease that can be treated pharmacologically. Recognition and prompt diagnosis are very important, because Wilson disease is fatal if left untreated. In this review, I summarize the pathogenesis and management of Wilson disease.

Zinc monotherapy is effective in Wilson's disease patients with mild liver disease diagnosed in childhood: a retrospective study

BACKGROUND

Wilson's disease (WD) evolves rapidly and is fatal if untreated. The treatment of WD patients with mild liver disease is not clearly defined. To address this issue, we evaluated long-term outcomes of three treatment regimens (D-penicillamine, zinc or both) in patients diagnosed in childhood.

METHODS

We retrospectively evaluated efficacy, compliance and reasons for treatment discontinuation in 42 WD patients (median age at diagnosis: 6 years; median follow-up: 12 years) with mild liver disease. Treatment duration for each treatment block until a medication change or completion of follow-up was analyzed. Events of change of treatment were evaluated using Kaplan-Meier analysis.

RESULTS

Total discontinuations due to treatment failure or adverse events were more frequent in patients receiving D-penicillamine (45%) or combination (36%) therapy than in patients receiving zinc (12%) (P = .001 and P = .02, respectively). Treatment failure was more frequent on D-penicillamine (28%) and combination therapy (36%) than on zinc (12%); the difference was statistically significant only between zinc and combination therapy (P = .03). First-line zinc monotherapy controlled WD-related liver disease in 13/15 patients (87%); the two subjects that failed on zinc were poor adherent. Zinc was effective in 3/5 (60%) patients that failed on D-penicillamine and combination regimens. All 15 D-penicillamine responders that switched to zinc had good control of liver disease at a median follow-up of 13.1 years. Among 6 D-penicillamine non-responders that switched to zinc, 4 (67%) responded. At follow-up completion, only 5/42 (12%) patients failed. Adverse event-induced discontinuation was significantly more frequent in patients on D-penicillamine than in patients receiving zinc (P = .03).

CONCLUSIONS

Zinc monotherapy is effective in controlling WD-related liver disease both as first-line and as maintenance treatment in patients with mild liver disease diagnosed in childhood.

Comprehensive analysis on clinical features of Wilson's disease: an experience over 28 years with 133 cases

OBJECTIVES

Here, we reported our experience over 28 years with 133 cases of patients with Wilson's disease (WD) in order to illustrate the diverse clinical presentation and to improve understanding and early diagnosis of WD.

METHODS

We reviewed the medical records of patients with WD at Shengjing Hospital of China Medical University from 1993 to 2011. The clinical manifestations and laboratory findings were analyzed. The diagnosis was based on the presence of Kayser-Fleisher (K-F) rings, low serum copper levels, low serum ceruloplasmin levels, increased urinary copper concentrations before or after penicillamine challenge.

RESULTS

Among them, 93 patients mainly presented with hepatic manifestations, 27 with neural abnormalities, and 13 presented with others. Age range at diagnosis was wide (3-74 years, average 13·2 years), and five patients were over 40 years. The oldest one was aged 74 years and presented with neuropsychiatric disorder. The positive rate of K-F rings was 93·0%. The serum ceruloplasmin decreased in 83·6% patients, 24-hour urinary copper increased in 88·1% patients, and serum copper decreased in 68·9% patients. About 79·7% of patients were diagnosed within 6 months, but only 33·1% were diagnosed at their initial medical consultation. There was a substantial delay of up to 15 years.

CONCLUSIONS

The clinical manifestation of WD is very diverse and no one feature is completely reliable. Doctors in many fields have opportunities to encounter this disease, and the most important thing is to be aware of the possibility of WD.

EGFP tags affect cellular localization of ATP7B mutants

AIMS

Wilson's disease is an autosomal recessive disorder of copper metabolism due to mutations within ATP7B gene. Clinical investigations indicate that ATP7B truncations are associated with an early age of onset when compared to its missense mutations. In vitro studies show that mislocalization of ATP7B mutants is involved in disease-causing mechanisms. Enhanced green fluorescent protein (EGFP) tags are commonly used in in vitro studies of cellular localization of ATP7B mutants. However, there is still much unknown about cellular localization of ATP7B truncations.

METHODS

Here, we subcloned full-length human wild-type, a missense mutation (T935M), and four truncating mutants (E332X, Q511X, Q547X, Q819X) of ATP7B into pEGFP-C1, pEGFP-N2 and pCMV-myc, and transfected Chinese hamster ovary (CHO) and SH-SY5Y cells with them, respectively.

RESULTS

ATP7B truncations all showed a diffuse and homogenous distribution pattern within the cytosol of CHO and SH-SY5Y cells, whereas its wild-type proteins and T935M mutation were clustered in the Golgi apparatus. Furthermore, we found that EGFP tags at N- or C-terminal would severely affect cellular localization of ATP7B truncations, and EGFP tags at N-terminal also have an influence on T935M localization.

CONCLUSION

EGFP tags may not be suitable for the detection of cellular localization of ATP7B mutants.

Spasmodic muscle cramps and weakness as presenting symptoms in Wilson disease

Wilson disease (WD) is an autosomal-recessive disorder of hepatic copper metabolism that has tremendous variability in its presentation. Phenotypic diversity of the disease can lead to delayed diagnosis. We describe a case of WD in a 10-year-old boy presenting with 3 months of increasingly intense, spasmodic lower extremity muscle cramps. Physical examination revealed tenderness on calf palpation and dark flat lesions over his ankles, knees, and elbows. Initial testing revealed creatine kinase of 302 IU/L (normal 24-248 IU/L), hemoglobin of 8.9 g/dL (11.5-15.5 g/dL), aspartate aminotransferase of 114 IU/L (16-52 IU/L), alanine aminotransferase of 54 IU/L (2-30 IU/L), and myoglobinuria. Extensive evaluation of his myopathy, including MRI and muscle biopsy, was negative. Additional laboratory tests revealed a prothrombin time of 21.3 seconds (11.8-15.5 seconds), total bilirubin of 1.4 mg/dL (<1 mg/dL), direct bilirubin of 0.5 mg/dL (<0.3 mg/dL), albumin of 2.1 g/dL (3.1-4.6 g/dL), a reticulocyte percentage of 4.5% (0.5%-2.5%), a negative Coombs direct antibody test, ceruloplasmin of 3 mg/dL (21-51 mg/dL), and 24-h urine copper of 393 μg/24 h (15-60 μg/24 h). Liver biopsy showed patchy advanced fibrosis, mild inflammation, positive staining for copper, and a tissue copper concentration of 768 µg/g (10-35 μg/g). Brain MRI revealed symmetric intrinsic T1 shortening within bilateral basal ganglia. Trientene therapy was initiated for WD. Symptoms and laboratory abnormalities resolved and remain normal at 21 months' follow-up. Musculoskeletal involvement in WD is uncommon and typically defined as bone demineralization, arthropathy, or hypokalemic muscle weakness. In patients with unexplained musculoskeletal symptoms and hepatic abnormalities, a diagnosis of WD should be considered and appropriate evaluation initiated.

Genetic defects in Indian Wilson disease patients and genotype-phenotype correlation

Wilson disease (WD) is caused by defects in ATP7B gene due to impairment of normal function of the copper transporting P-type ATPase. This study describes a comprehensive genetic analysis of 199 Indian WD patients including mutations detected in our previous studies, undertakes functional assessment of the nucleotide variants in ATP7B promoter and correlates genotype with disease phenotype. The patient cohort harbors a total of 10 common and 48 rare mutations in the coding region of ATP7B including 21 novel changes. The common mutations represent 74% of characterized coding mutant alleles with p.C271X (63/260) and p.G1101R (7/31) being the most prevalent in eastern and western Indian patients, respectively. The mutation spectrum between east and west is mostly different with only three mutations (p.G1061E, p.N1270S and p.A1049A-fs) being shared between both the groups. Eight novel and 10 reported variants have been detected in the promoter and non-coding regions (5' and 3'UTRs) of ATP7B. Promoter reporter assay demonstrated that 3 novel variants and 5 reported polymorphisms alter the gene expression to a considerable extent; hence might play important role in ATP7B gene regulation. We devised the neurological involvement score to capture the spectrum of neurological involvement in WD patients. By utilizing the age at onset, neurological involvement score and ATP7B mutation background, we generated a genotype-phenotype matrix that could be effectively used to depict the phenotypic spectra of WD affected individuals and serve as a platform to identify prospective "outliers" to be investigated for their remarkable phenotypic divergence.

Novel ATPase Cu(2+) transporting beta polypeptide mutations in Chinese families with Wilson's disease

Wilson's disease (WD) is an autosomal recessive inherited disorder caused by mutations in the ATPase Cu(2+) transporting beta polypeptide gene (ATP7B). The detailed metabolism of copper-induced pathology in WD is still unknown. Gene mutations as well as the possible pathways involved in the ATP7B deficiency were documented. The ATP7B gene was analyzed for mutations in 18 Chinese Han families with WD by direct sequencing. Cell viability and apoptosis analysis of ATP7B small interfering RNA (siRNA)-treated human liver carcinoma (HepG2) cells were measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and Hoechst 33342 staining. Finally, the expression of B-cell CLL/lymphoma 2 (BCL2), BCL2-associated X protein (BAX), sterol regulatory element binding protein 1 (SREBP1), and minichromosome maintenance protein 7 (MCM7) of ATP7B siRNA-treated cells were tested by real-time polymerase chain reaction (real-time PCR) and Western blot analysis. Twenty different mutations including four novel mutations (p.Val145Phe, p.Glu388X, p.Thr498Ser and p.Gly837X) in the ATP7B gene were identified in our families. Haplotype analysis revealed that founder effects for four mutations (p.Arg778Leu, p.Pro992Leu, p.Ile1148Thr and p.Ala1295Val) existed in these families. Transfection of HepG2 cells with ATP7B siRNA resulted in decreased mRNA expression by 86.3%, 93.1% and 90.8%, and decreased protein levels by 58.5%, 85.5% and 82.1% at 24, 48 and 72 hours, respectively (All P<0.01). In vitro study revealed that the apoptotic, cell cycle and lipid metabolism pathway may be involved in the mechanism of WD. Our results revealed that the genetic cause of 18 Chinese families with WD and ATP7B deficiency-induce apoptosis may result from imbalance in cell cycle and lipid metabolism pathway.

Wilson disease mutation pattern with genotype-phenotype correlations from Western India: confirmation of p.C271* as a common Indian mutation and identification of 14 novel mutations

Wilson disease (WD) is an autosomal recessive disorder resulting from mutations in the ATP7B gene, with over 600 mutations described. Identification of mutations has made genetic diagnosis of WD feasible in many countries. The heterogeneity of ATP7B mutants is, however, yet to be identified in the Indian population. We analyzed the mutational pattern of WD in a large region of Western India. We studied patients (n = 52) for ATP7B gene mutations in a cohort of families with WD and also in first-degree relatives (n = 126). All 21 exon-intron boundaries of the WD gene were amplified and directly sequenced. We identified 36 different disease-causing mutations (31 exonic and five intronic splice site variants). Fourteen novel mutations were identified. Exons 2, 8, 13, 14, and 18 accounted for the majority of mutations (86.4%). A previously recognized mutation, p.C271*, and the novel mutation p.E122fs, were the most common mutations with allelic frequencies of 20.2% and 10.6%, respectively. Frequent homozygous mutations (58.9%) and disease severity assessments allowed analysis of genotype-phenotype correlations. Our study significantly adds to the emerging data from other parts of India suggesting that p.C271* may be the most frequent mutation across India, and may harbor a moderate to severely disabling phenotype with limited variability.

Decreased serum antioxidant capacity in patients with Wilson disease is associated with neurological symptoms

BACKGROUND & AIMS

Wilson disease (WD) is an inherited disorder of copper disposition caused by an ATP7B transporter gene mutation, leading to copper accumulation in predisposed tissues. In addition to a genetic predisposition, other factors are likely to contribute to its clinical manifestation. The aim of the study was to assess whether oxidative stress affects the phenotypic manifestation of WD.

METHODS

In 56 patients with WD (29 men; 26 with the hepatic form, 22 with the neurologic form, and eight asymptomatic; mean age 38.5 ± 12 years), total serum antioxidant capacity (TAC) and inflammatory parameters (hs-CRP, IL-1β, IL-2, IL-6, IL-10, and TNF-α) were analyzed and related to the clinical manifestation, and mutations of the ATP7B gene. The control group for the TAC and inflammatory parameters consisted of 50 age- and gender-matched healthy individuals.

RESULTS

WD patients had a significantly lower TAC (p < 0.00001), lower IL-10 levels (p = 0.039), as well as both higher IL-1β (p = 0.019) and IL-6 (p = 0.005) levels compared to the control subjects. TNF-α, hs-CRP, and IL-2 did not differ from the controls. Patients with the neurological form of WD had a significantly lower TAC than those with the hepatic form (p < 0.001). In addition, the lower TAC was associated with the severity of the neurological symptoms (p = 0.02). No relationship between the inflammatory parameters and clinical symptoms was found.

CONCLUSIONS

Data from our study suggest that the increased oxidative stress contributes significantly to the clinical manifestation of WD; as a lower TAC is associated with the neurological symptoms in WD patients.

Wilson's disease: an analysis of 28 Brazilian children

OBJECTIVES

Clinical-laboratory and evolutionary analysis of twenty-eight patients with Wilson's disease.

METHODS

Twenty-eight children (twelve females and sixteen males) with Wilson's disease were evaluated retrospectively between 1987 and 2009, with a follow-up of 72 months (1 - 240 months). The clinical, laboratory, and histologic features at diagnosis were recorded at the end of the study.

RESULTS

The median age at diagnosis was 11 years (2 - 18 years). Twelve patients were asymptomatic, seven had hepatitis symptoms, five had raised aminotransferase levels, three had hepatomegaly associated with neurological disorders, one had fulminant hepatitis with hemolytic anemia, and six patients presented with a Kayser-Fleischer ring. A histological analysis revealed that six children had chronic hepatitis, seven had cirrhosis, two had steatosis, one had portal fibrosis, and one had massive necrosis. The treatment consisted of D-penicillamine associated with pyridoxine for 26 patients. Adverse effects were observed in the other two patients: one presented with uncontrollable vomiting and the other demonstrated elastosis perforans serpiginosa. At the end of the study, all 26 treated patients were asymptomatic. Twenty-four of the patients were treated with D-penicillamine and pyridoxine, and two were treated with trientine and zinc sulfate. A liver transplant was performed in one patient with fulminant hepatitis, but the final patient died 48 hours after admission to the intensive care unit.

CONCLUSIONS

Family screenings associated with early treatment are important in preventing Wilson's disease symptoms and potentially fatal disease progression. The study suggests that Wilson's disease must be ruled out in children older than two years presenting with abnormal levels of hepatic enzymes because of the heterogeneity of symptoms and the encouraging treatment results obtained so far.

DNA and RNA studies for molecular characterization of a gross deletion detected in homozygosity in the NH2-terminal region of the ATP7B gene in a Wilson disease patient

Wilson disease is an autosomal recessive disorder caused by defective function of the copper transporting protein ATP7B. Approximately 520 Wilson disease-causing mutations have been described to date. In this study we report the use of DNA and RNA analysis for molecular characterization of a gross deletion of the ATP7B gene detected in homozygosity in a Wilson disease patient. The c.51+384_1708-953del mutation spans an 8798 bp region of the ATP7B gene from exon 2 to intron 4. The results obtained suggest that the combination of DNA and RNA analyses can be used for molecular characterization of gross ATP7B deletions, thus improving genetic counselling and diagnosis of Wilson disease. Moreover these studies, help to better establish the molecular mechanisms producing Wilson disease.

Systems biology approach to Wilson's disease

Wilson's disease (WD) is a severe disorder of copper misbalance, which manifests with a wide spectrum of liver pathology and/or neurologic and psychiatric symptoms. WD is caused by mutations in a gene encoding a copper-transporting ATPase ATP7B and is accompanied by accumulation of copper in tissues, especially in the liver. Copper-chelation therapy is available for treatment of WD symptoms and is often successful, however, significant challenges remain with respect to timely diagnostics and treatment of the disease. The lack of genotype-phenotype correlation remains unexplained, the causes of fulminant liver failure are not known, and the treatment of neurologic symptoms is only partially successful, underscoring the need for better understanding of WD mechanisms and factors that influence disease manifestations. Recent gene and protein profiling studies in animal models of WD began to uncover cellular processes that are primarily affected by copper accumulation in the liver. The results of such studies, summarized in this review, revealed new molecular players and pathways (cell cycle and cholesterol metabolism, mRNA splicing and nuclear receptor signaling) linked to copper misbalance. A systems biology approach promises to generate a comprehensive view of WD onset and progression, thus helping with a more fine-tune treatment and monitoring of the disorder.

Late diagnosed Wilson disease with hepatic and neurological manifestations

A 50-year-old woman was referred to our hospital due to liver dysfunction and progressive neurological symptoms. She had previously been diagnosed with nonalcoholic steatohepatitis (NASH). Ursodeoxycholic acid (UDCA) had effectively normalized her serum aminotransferase levels, however, she presented with loss of balance, dysarthria and difficulty in handwriting. Autoantibodies and hepatitis virus markers were negative. Serum ceruloplasmin and copper levels were noted to be 9 mg/dL and 32 µg/dL, respectively. The 24-h urinary copper excretion was 331.8 µg/day. Kayser-Fleischer ring was demonstrated. Histological examination of the liver revealed inflammatory infiltrate and fibrosis, and the hepatic copper concentration was 444.4 µg/g dry weight. We diagnosed her as having Wilson disease and started treatment with trientine. Immuohistochemistry for keratin 8 and p62 demonstrated Mallory-Denk bodies. Many of the p62-expressing cells were positive for 4-Hydroxy-2-nonenal (HNE). Few Ki-67-positive hepatocytes were present in the liver. Wilson disease is one of the causes of NASH and UDCA may be a supportive therapeutic agent for Wilson disease. Cell proliferation is suppressed under copper-loaded conditions and this phenomenon may be associated with the clinical course of Wilson disease.

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.

Long-term follow-up of Wilson disease: natural history, treatment, mutations analysis and phenotypic correlation

BACKGROUND AND AIMS

Wilson disease (WD) is an inherited disorder of copper metabolism. When treated, the outcome can be excellent, although the long-term survival has yet to be well documented. The aim of this study was to describe the long-term outcome of a cohort of patients with WD and to assess those factors affecting the phenotypic manifestation of WD.

METHODS

The presence of mutations to the ATP7B gene, the clinical manifestations, treatments and the long-term outcomes were analysed retrospectively in 117 patients with WD (59 men and 58 women, aged at evaluation 38.5 ± 11, range 16-63 years).

RESULTS

Fifty-five patients with a neurological presentation, 51 patients with a hepatic presentation and 11 asymptomatic patients were followed up for an average of 15.1 ± 10 years (median 12 years, range 1-41 years). The H1069Q ATP7B gene mutation was the most frequent genetic variant (54.3%); the frequency of this mutation did not differ between patients with either the hepatic or the neurological presentation (P = 0.099). d-penicillamine or zinc salts (81 and 17% respectively) were used for treatment, and three patients underwent liver transplantation. The majority of symptomatic patients became asymptomatic, or improved, during the follow-up (82% patients with hepatic presentation, 69% with neurological presentation). The long-term survival of patients with WD did not differ from that of the general Czech population (P = 0.95).

CONCLUSIONS

Long-term follow-up shows a satisfactory response in the great majority of adequately treated patients with WD and survival coincides with that of the general population.

Re-evaluation of the diagnostic criteria for Wilson disease in children with mild liver disease

The diagnosis of Wilson disease (WD) is challenging, especially in children. Early detection is desirable in order to avoid dramatic disease progression. The aim of our study was to re-evaluate in WD children with mild liver disease the conventional diagnostic criteria and the WD scoring system proposed by an international consensus in 2001. Forty children with WD (26 boys and 14 girls, age range = 1.1-20.9 years) and 58 age-matched and sex-matched patients with a liver disease other than WD were evaluated. Both groups were symptom-free and had elevated aminotransferases as predominant signs of liver disease. In all WD patients, the diagnosis was supported by molecular analysis, the liver copper content, or both. A receiver operating characteristic (ROC) analysis of ceruloplasmin at the cutoff value of 20 mg/dL showed a sensitivity of 95% [95% confidence interval (CI) = 83%-99.4%] and a specificity of 84.5% (95% CI = 72.6%-92.6%). The optimal basal urinary copper diagnostic cutoff value was found to be 40 μg/24 hours (sensitivity = 78.9%, 95% CI = 62.7%-90.4%; specificity = 87.9%, 95% CI = 76.7%-95%). Urinary copper values after penicillamine challenge did not significantly differ between WD patients and control subjects, and the ROC analysis showed a sensitivity of only 12%. The WD scoring system was proved to have positive and negative predictive values of 93% and 91.6%, respectively.

CONCLUSION

Urinary copper excretion greater than 40 μg/24 hours is suggestive of WD in asymptomatic children, whereas the penicillamine challenge test does not have a diagnostic role in this subset of patients. The WD scoring system provides good diagnostic accuracy.

Genetic analysis of BIRC4/XIAP as a putative modifier gene of Wilson disease

Wilson disease (WD) is an autosomal-recessive copper overload disorder caused by mutations in the copper-transporting adenosine triphosphatase (ATPase) ATP7B. It presents with a highly variable clinical phenotype ranging from asymptomatic to fulminant hepatic failure or progressive neurological involvement. No clear genotype-phenotype correlation has been established. Thus, variants in modifier genes could have an impact on WD manifestation and severity. Recently, the antiapoptotic protein baculoviral IAP repeat-containing protein 4 BIRC4/XIAP has been suggested as a regulator of copper-induced cell death. With the aim of investigating a putative role of BIRC4/XIAP as modifier gene in individuals with copper overload, we analyzed a WD patient cohort (n = 98) for sequence variants at the BIRC4/XIAP locus. When compared with clinical data, the previously described coding single nucleotide polymorphisms (SNPs) at the BRIC4/XIAP locus (rs28382721, rs28382722, rs28382723, rs5956583, rs28382740, rs12838858, rs28382741) did not correlate with age of onset or clinical presentation in our collective. However, three previously unreported variants in the BIRC4/XIAP gene were identified (c.1-26 T > G; c.1408A > T; p.T470S; c.1019A > G; p.N340S). The two patients with variants leading to amino acid exchanges in the BIRC4/XIAP protein showed a remarkably early disease onset at the age of 5 years. Furthermore, one of these patients was only heterozygous for disease-causing mutations in the ATP7B gene. In summary, these data emphasize the need to further elucidate a role of BIRC4/XIAP variants as putative pathogenetic factors in copper overload disorders.