Mutations In ATP7B Gene Research Articles

Unusual Confluence: Exploring the Association of Biliary Atresia, Wilson Disease, and Iron Overload

ABSTRACT The case involves a 33-year-old man with biliary atresia, Wilson disease (WD), and iron overload. Biliary atresia, a cholangiodestructive disease, leads to cirrhosis if untreated. WD, caused by ATP7B gene mutations, results in copper accumulation affecting the liver and brain. Iron overload can be seen in cases of WD and with hereditary hemochromatosis gene mutations. The patient's concurrent presentation of these conditions poses a unique clinical challenge. Elevated iron levels may worsen WD outcomes. A detailed history and physical examination, genetic testing, and close follow-up are crucial. The case highlights the need for increased awareness and vigilant monitoring of patients with overlapping liver diseases.

Low penetrance of frequent ATP7B mutations explains the low prevalence of Wilson disease. Lessons from real-life registries.

Background & AimsWilson disease (WD) is a copper metabolism disorder caused by mutations in ATP7B gene, with significant clinical variability. Several studies have analyzed the prevalence and penetrance of mutations. We evaluated both characteristics for our more frequent mutations. MethodsEvaluation of 260 patients from the National Registry: clinical, analytical and genetic data. Estimation of homozygotes and total cases according to Hardy-Weinberg equilibrium and comparison with Registry records. ResultsThe estimated number of homozygotes were higher than registered: p.Met645Arg (1949/6), p.His1069Gln (20/8), p.Leu708Pro (63/24) and p.Gly869Arg (147/0). p.Met645Arg homozygotes presented less cirrhosis at diagnosis, extrahepatic disease and Kayser-Fleischer ring (KFR) and more presymptomatic cases and diagnosis after 40 years of age than p.Leu708Pro and p.His1069Gln homozygotes. p.Met645Arg homozygotes presented more late diagnosis than p.Met645Arg compound heterozygotes. Compound heterozygotes carrying p.Met645Arg or p.Gly869Arg showed less cirrhosis at diagnosis, KFR and neurological symptoms and more hepatic and presymptomatic cases, despite clearly low ceruloplasmin levels. The estimated prevalence was 1:3.785, predicting more than 10.500 patients. ConclusionsThe widespread mutations p.Met645Arg and p.Gly869Arg show low penetrance. WD might be underdiagnosed in Spain due to less severe phenotype of the most frequent mutations, a crucial fact to avoid misdiagnosis and to offer early therapy.

Investigating common mutations in ATP7B gene and the prevalence of Wilson's disease in the Thai population using population-based genome-wide datasets.

Wilson's disease (WD) is a rare metabolic disorder caused by variations in the ATP7B gene. It usually manifests hepatic, neurologic, and psychiatric symptoms due to excessive copper accumulation. The prevalence of WD and its common variants differ across populations. This study aimed to examine these aspects of WD within the Thai population, where information has been limited. We reviewed ClinVar and the Wilson Disease Mutation Database, organizing variants classified as pathogenic or likely pathogenic in one or both databases as "relaxed" and "strict" lists. Allele frequencies were estimated from genotyping array data (Asian Screening Array: ASA; Illumina Corp, CA) of 6291 Thai subjects, which also underwent genotype imputation. The prevalence of WD in the Thai population was estimated assuming Hardy-Weinberg Equilibrium. The strict list yielded a prevalence of 1/24,128 (carrier frequency=1/78), while the relaxed list yielded a prevalence of 1/9971 (carrier frequency=1/50). The most common WD variants in Thai subjects were c.2333 G > T, c.3443 T > C, and c.813 C > A from the strict list, and c.3316 G > A and c.2605 G > A from the relaxed list. The ASA chip covered approximately 59 and 24% of WD variants from the strict and relaxed lists, respectively. Based on the estimated prevalence, a carrier screening program for WD is not currently required in Thailand. However, as genotyping services become more affordable and accessible, such a program would facilitate early identification, treatment, and prevention of WD.

Analysis of clinical and genetic characteristics of the severe liver disease phenotype in patients with hepatolenticular degeneration

Objective: To investigate the clinical and genetic characteristics and predictive role of the severe liver disease phenotype in patients with hepatolenticular degeneration (HLD). Methods: Inpatients with HLD confirmed at Xinhua Hospital affiliated with Shanghai Jiao Tong University School of Medicine from January 1989 to December 2022 were selected as the research subjects. Clinical classification was performed according to the affected organs. Patients with liver disease phenotypes were classified into the liver disease group and further divided into the severe liver disease group and the ordinary liver disease group. The clinical characteristics and genetic variations were compared in each group of patients. The predictive indicators of patients with severe liver disease were analyzed by multiple regression. Statistical analysis was performed using the t-test, Mann-Whitney U test, or χ(2) test according to different data. Results: Of the 159 HLD cases, 142 were in the liver disease group (34 in the severe liver disease group and 108 in the ordinary liver disease group), and 17 were in the encephalopathy group. The median age of onset was statistically significantly different between the liver disease group and the encephalopathy group [12.6 (7.0, 13.3) years versus 16.9 (11.0, 21.5) years, P<0.01]. 156 ATP7B gene mutation sites were found in 83 cases with genetic testing results, of which 54 cases carried the p.Arg778Leu gene mutation (allele frequency 46.2%). Compared with patients with other types of gene mutations (n=65), patients with homozygous p.Arg778Leu mutations (n=18) had lower blood ceruloplasmin and albumin levels, a higher prognostic index, Child-Pugh score, an international normalized ratio, and prothrombin time (P<0.05). Hemolytic anemia, corneal K-F ring, homozygous p.Arg778Leu mutation, and multiple laboratory indexes in the severe liver disease group were statistically significantly different from those in the ordinary liver disease group (P<0.05). Multivariate logistic regression analysis showed that the predictive factors for severe liver disease were homozygous p.Arg778Leu mutation, total bilirubin, and bile acids (ORs=16.512, 1.022, 1.021, 95% CI: 1.204-226.425, 1.005-1.039, and 1.006-1.037, respectively, P<0.05). The drawn ROC curve demonstrated a cutoff value of 0.215 3, an AUC of 0.953 2, and sensitivity and specificity of 90.91% and 92.42%, respectively. Conclusion: Liver disease phenotypes are common in HLD patients and have an early onset. Total bilirubin, bile acids, and the homozygous p.Arg778Leu mutation of ATP7B is related to the severity of liver disease in HLD patients, which aids in predicting the occurrence and risk of severe liver disease.

Genotype-phenotype relationship and genetics study of 115 cases with Wilson's disease

Objective: To explore the genotype-phenotype relationship of Wilson's disease (WD) and further study the mutation spectrum in the ATP7B gene. Methods: The clinical data and genetic test results of 115 cases with WD diagnosed in the First Affiliated Hospital of Zhengzhou University from 2015 to 2022 were retrospectively analyzed. The rank sum test was used for quantitative data comparison, and χ(2) test was used for count data comparison. Multivariate logistic regression was used to analyze the relationship between patients' genotype and phenotype. Results: The onset of liver manifestations (hepatic type) accounted for 60.9%, neurological symptoms (cerebral type) for 13.0%, and mixed hepato-cerebral symptoms for 26.1%. Presymptomatic individuals (hepatic types) accounted for 62.9%. Next-generation sequencing- diagnosed WD cases accounted for 87.8%. Combined multiplex ligation-dependent probe amplification assay-diagnosed WD cases accounted for 89.6%. A single case with a detected pathogenic locus accounted for 10.4%. The diagnostic rate of WD by genetic testing combined with clinical data was 100%. A total of 76 ATP7B mutations were detected, and the top three mutation frequencies were c.2333G>T (p.Arg778Leu) (30.7%), c.2975C>T (p.Pro992Leu) (7.3%), and c.2621C>T (p.Ala874Val) (6.4%). The mutations were mainly distributed in exons 8, 11-13, and 15-18, accounting for more than 90% of the total mutations. Eight new mutations were found, including c.3724G>A (p.Glu1242Lys), c.3703G>C (p.Gly1235Arg), c.3593T>C (p.Val1198Ala), c.2494A>C (p.Lys832Gln), c.1517T>A (p.Ile506Lys), c.484G>T (p.Glu162Ter), c.1870-49A>G, and the missing of exons 10-21. Liver histopathology showed cellular edema, degeneration, inflammation, and necrosis, as well as a 42.8% copper staining positive rate. Genotype-phenotype analysis showed that the p.Arg778Leu mutation had higher alanine aminotransferase (ALT) levels than those carrying other mutations (P=0.024), while the homozygous mutation of p.Arg778Leu was associated with cerebral-type patients (P=0.027). Conclusion: Genetic testing plays an important role in the diagnosis of WD. p.Arg778Leu is the first high-frequency mutation in the Chinese population, and patients carrying it have higher ALT levels. The p.Arg778Leu homozygous mutation is prone to causing cerebral-type WD. This study expands the ATP7B gene mutation spectrum.

Identification of the ATP7B gene mutations in the algerian population

Identification of the ATP7B gene mutations in the algerian population

A rare presentation of Wilson disease: a case report

Wilson Disease results from autosomal recessive mutation in ATP7B gene which leads to reduced formation of ceruloplasmin protein in the body that acts as a copper transporter. Due to its deficiency, there is the build-up of copper in the liver and brain among other organ systems and it leads to the development of various clinical abnormalities but commonly presents either as hepatic dysfunction and/or cirrhosis in young patients with movement disorder. Here we present a case that presented with hypoglycemia and hypothermia in absence of any infection, drug abuse or metabolic abnormality. He was later diagnosed as Wilson disease. Wilson Disease is mostly thought of hepatic /neurological disease. Contrary to this Wilson’s disease is a multisystem disease affecting multiple organ system including, kidneys, endocrine system and musculoskeletal system and can present with manifestations of above-mentioned systems.

Systematic Analysis and Insights Into the Mutation Spectrum and Ethnic Differences in ATP7B Mutations Associated With Wilson Disease.

ATP7B (ATPase copper transporting beta gene) is constituted of 21 exons, and codes for a 1465 amino acid. The protein of ATP7B plays an key role of copper metabolism. Many previous reports indicated that mutations in ATP7B are well known to cause defective copper transporting copper-transporting ATPase 2 protein leading to the accumulation of copper, resulting the Wilson disease. The meta-analysis was performed to comprehensive gain a thorough grasp of the spectrum of genetic variations. A meta-analysis was conducted according to the guiding of PRISMA. aiming to assess the diversity and frequency of mutations in the ATP7B gene, with an emphasis on mutations located within specific exons. The dataset of detected mutations within their positions, types as well as nomenclature, were recorded from previous studies (spanning the year from 2013 to 2023). The analysis focused on exon-specific variations and their prevalence across different populations. A total of 40 studies were enrolled into current data analysis. Our comprehensive study revealed a variety of mutations, most notably over 50% of single nucleotide changes described, distributed over the 21 exons of the gene. Focusing on the exon 8, itisplayed the most diversity of mutations, with 18 studies identifying 53 unique variants, the majority of which were missense mutations (81.13%). Additionally, the variations c.2333G>A/T (p.R778Q/L), c.2305A>G (p.M769V), c.2336G>A (p.W779*), and c.2304dupC (p.M769HfsX26) are reported in many populations. The weighted mean of variants' proportion was used to calculate the pooled estimate of these percentages, which were 14.19% for c.2333G>A/T (p.R778Q/L), 2.70% for c.2305A>G (p.M769V), 1.42% for c.2336G>A (p.W779*), and 2.33% for c.2304dupC (p.M769HfsX26). This design demonstrate to identify the spectrum of ATP7B gene's mutations, especially exon 8, offering important insights into the prevalence and significance of exon 8 mutations. Understanding the mutation in the ATP7B gene offers insights into the mechanisms behind WD and guides strategies for diagnosis and treatment.

A Case of Wilson's Disease Suspected to Involve a Novel Genetic Mutation of ATP7B Gene, Requiring a Differential Diagnosis with Non-alcoholic Steatohepatitis.

A 19-year-old Japanese man was referred for a further evaluation of liver dysfunction. Despite the absence of symptoms or obesity, the liver biopsy results were consistent with non-alcoholic steatohepatitis. Subsequent investigations revealed low serum ceruloplasmin, increased urinary copper excretion, and a known mutation c.3809A>G (p.Asn1270Ser) in the copper-transporting enzyme P-type ATPase (ATP7B) gene, leading to a diagnosis of Wilson's disease. A previously unreported variant, i.e., c.3866A>T (p.Asp1289Val) was detected on the patient's other allele and was considered a novel mutation, classified as 'likely pathogenic' according to the American College of Medical Genetics guidelines.

ATP7B Gene Variant Profile İdentified by NGS in Wilson’s Disease

Background: Wilson’s disease (WD) is a copper metabolism disorder caused by ATP7B gene mutations and shows an autosomal recessive pattern of inheritance. We aimed to contribute to the mutation profile of ATP7B and show demographic and phenotypic differences in this study. Materials and methods: The clinical and demographic characteristics of patients who underwent ATP7B gene sequence analysis using next-generation sequencing were evaluated to improve genotype-phenotype correlation in WD. Results: An uncertain significance (D563N) and seven likely pathogenic (Y532D, Y715Y, T977K, K1028*, E1086K, A1227Pfs*103, and E1242K) variants were identified as associated with WD. Uniparental disomy was detected in one case. Conclusion: Our work expanded the ATP7B variant spectrum and pointed to clinical heterogeneity in ATP7B variants among patients with WD. All symptomatic patients had hepatic involvement and were clinically and/or genetically diagnosed with WD in the pediatric period. T977K, A1003V, H1069Q, E1086K, and N1270S variants were associated with hepatic failure.

Can Patients with Wilson's Disease Develop Copper Deficiency?

Wilson's disease (WD) is a rare genetic condition characterized by a copper overload in organs secondary to mutation in ATP7B gene. Lifelong decoppering treatments are the keystone of the treatment but must be regularly adapted to obtain a correct copper balance and could lead to copper deficiency (CD). Study the characteristics of CD in WD patients. CD cases from our cohort of 338 WD patients have been investigated. CD was defined by the association of serum copper, exchangeable copper and urinary copper excretion assays less than two standard deviations from the mean with cytopenia and/or neurological damage of spinal cord origin. A systematic review of literature about cases of CD in WD patient was performed in PubMed database according to PRISMA guidelines. Three WD patients were diagnosed with CD in our cohort. Review of the literature found 17 other patients. Most of the patients had anemia and neutropenia associated with neurological symptoms (especially progressive posterior cord syndrome). All the patients were treated with Zinc salts and the symptoms occurred more than a decade after the initiation of treatment. The adaptation of the treatment allowed a correction of the cytopenia but only a partial improvement of the neurological symptoms. WD patients can develop CD after many years of zinc therapy. Anemia and neutropenia are red flags that should evoke CD.

A261 SEVERE ACUTE LIVER INJURY SECONDARY TO WILSON’S DISEASE: A CASE REPORT AND REVIEW OF THE LITERATURE

Abstract Background Wilson’s disease is autosomal recessive and rare (prevalence 1/30000-1/50000) caused by mutations in the ATP7B gene involved in copper excretion. Copper deposition drives hepatic injury, along with neuropsychiatric-ophthalmologic, and hematologic symptoms. Leipzig criteria greater than 4 establishes the diagnosis. Purpose We report a case of severe liver injury secondary to probable Wilson’s disease. Method Literature review of diagnosis, management including emerging therapies was performed using PubMed. Result(s) A 29-year-old otherwise healthy male with no family history of liver disease presented with abdominal pain, jaundice, and severe acute liver injury (ALT 1534 U/L ALP 114 U/L bilirubin 113 umol/L) initially misdiagnosed as hepatitis A in community urgent care. He had worsening liver injury (ALT 1809 U/L bilirubin 411 umol/L), with normal INR and no encephalopathy over an additional 3 weeks and was admitted to our tertiary care centre for further work up. History did not reveal viral prodromes, herbals or natural remedies. CBD oil was the only potential exposure, though longstanding use of the same brand argued against this as a cause. Chronic liver disease workup was negative (viral hepatitides, SARS-CoV-2, alpha-1-antitrypsin, acetaminophen level, iron profile, and comprehensive Mitogen autoantibody panel). Patent vasculature on Doppler US. Liver biopsy showed diffuse lobular inflammation, hepatocyte necrosis, 30% parenchymal involvement, primarily lymphocytes with some eosinophils and plasma cells, and no viral inclusions suggesting acute hepatitis with drugs or viral hepatitis as etiologies. The 24-hour urine copper was elevated at 2.19 umol/d (&amp;lt;0.80). Biopsy copper dry weight 60mcg/g (N&amp;lt;50; &amp;gt;250 diagnostic). Normal ceruloplasmin 0.30g/L and serum copper 25.8 umol/L. MRI brain not suggestive of Wilson’s disease, no Kayser-Fleischer rings on Ophthalmology assessment, and no hemolysis. Given a Leipzig score of 3 suggesting possible Wilson’s disease he was started on penicillamine 1500mg daily. Five weeks later he had serologic (ALT 1061 U/L bilirubin 128 umol/L) improvement, yet elevated elastography at 22kPa IQR 5% likely due to inflammation. Given coverage issues, he was switched to compassionate trientine 500mg BID with further improvement (ALT 347 U/L bilirubin 26 umol/L). Sequencing for ATP7B gene mutations are pending (Blueprint Genetics). Conclusion(s) Wilson’s disease should be considered in those with hepatic or neuropsychiatric symptoms, transaminases in the 1000s or acute liver failure. Treatment is lifelong with typically good prognosis and is fatal if untreated. Treatment options include chelators D-penicillamine (first line, with side effects including proteinuria and worsened neurological symptoms) and trientine (fewer side effects). Zinc prevents copper absorption and can be used in asymptomatic patients. Transplant in acute liver failure and end-stage liver disease is guided by the King’s score. Several novel therapies including gene therapy are in development. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

New ATP7B Gene Mutation in a Brazilian Patient with Wilson Disease.

Wilson disease (WD) is an autosomal recessive disorder of copper metabolismPatient age should not exclude WD, and symptoms compatible with WD should raise suspicion for WD even in older people.Genetic sequencing is an important tool in the discovery of new genetic mutations.

S3255 A Novel Mutation in ATP7B Gene: A Rare Manifestation of Wilson’s Disease With Liver Failure

Introduction: Wilson’s disease (WD) is a rare genetic condition characterized by excess copper build. Due to the presence of several genotypic and phenotypic variances; diagnosis can be challenging. We report a case of acute liver failure due to a novel ATP7B gene mutation, which has never been reported before. Case Description/Methods: A 16-year-old previously healthy male presented to the hospital with abdominal pain, nausea and vomiting for 3 days. Family history was significant for a sister who passed away due to “hepatitis”, he denied using alcohol or Tylenol; of note, parents immigrated from Honduras. On examination he was hemodynamically stable, jaundiced with marked scleral icterus, furthermore he was also lethargic and somnolent. His labs showed acute liver failure and acute kidney injury. Further workup included genetic testing with, alpha 1-antitrypsin, copper, ceruloplasmin and iron studies. Serum toxicology was negative. Infectious and autoimmune work-up was performed including ANA, anti-smooth muscle antibody; EBV, HSV, CMV, Hepatitis panel, VZV serologies; total IgG and subclasses, IgA, IgM, soluble IL-2, and Treponema Cruzi, which all came back negative other than low ceruloplasmin 6.0 mg/dL, and high 24hr urine copper excretion. Patient was diagnosed with decompensated liver failure due to Wilson’s disease and thus was listed for liver transplant at MELD-Na of 41. He later underwent orthotopic liver transplant. Of note, his detailed genetic studies with whole exome sequencing (WES) identified, two likely pathogenic ATP7B variants (c.3446G >C & c.2355G >A) (see Table-1). Postoperatively, he improved considerably. Moreover, patient and his entire family were also seen by genetic counselor once he was discharged home. Discussion: Wilson's disease is an autosomal recessive disease involving ATP7B gene, responsible for copper metabolism. Around 1019 mutations for ATP7B gene have been reported in literature. In our patient, p.(G1149A) variant was inherited from his father and has been reported before, however p.(K785=) variant has been unreported. This mutation alters the last nucleotide of the exon and causes aberrant splicing (see Figure-1). The fact that our patient exclusively had liver failure without any other organ system involvement in the setting of a novel mutation makes it a unique case for gastroenterologists for timely diagnosis and management of WD. Early treatment with copper chelators and zinc salts can not only halt the disease progression but may also prevent end organ damage.Figure 1.: A diagrammatic representation of mutated splicing site. Splicing is a process whereby introns (non-coding part) of mRNA are removed allowing for joining of exons (coding part of mRNA) resulting in mature mRNA which is then used for protein synthesis. The p.(K785=) mutation in ATP7B gene destroys the splicing donor site affecting downstream protein production leading to a dysfunctional copper metabolism. Table 1. - Causative Variant(s) in Disease Genes Associated with Reported Phenotype Gene Disease Mode of Inheritance Variant Zygosity Inherited Form Classification ATP7B ATP7B-related Wilson disease Autosomal c.3446 G >C Heterozygous Father Likely Pathogenic Recessive p.(G1149A) Variant ATP7B ATP7B-related Wilson disease Autosomal c.2355 G >A Heterozygous Unknown Likely Pathogenic Recessive p.(K785=) Variant

Liver cirrhosis prediction for patients with Wilson disease based on machine learning: a case-control study from southwest China.

ObjectivesWilson disease (WD) is a rare autosomal recessive disease caused by an ATP7B gene mutation. Liver cirrhosis is an important issue that affects the clinical management and prognosis of WD patients. Blood routine examination is a potential biomarker for predicting the occurrence of liver cirrhosis in WD. We aim to construct a predictive model for the occurrence of liver cirrhosis using general clinical information, blood routine examination, urine copper, and serum ceruloplasmin through a machine learning approach.MethodsCase–control study of WD patients admitted to West China Fourth Hospital between 2005 and 2020. Patients with a score of at least four in scoring system of WD were enrolled. A machine learning model was constructed by EmpowerStats software according to the general clinical data, blood routine examination, 24 h urinary copper, and serum ceruloplasmin.ResultsThis study analyzed 346 WD patients, of which 246 were without liver cirrhosis. And we found platelet large cell count (P-LCC), red cell distribution width CV (RDW-CV), serum ceruloplasmin, age at diagnosis, and mean corpuscular volume (MCV) were the top five important predictors. Moreover, the model was of high accuracy, with an area under the receiver operating characteristic curve of 0.9998 in the training set and 0.7873 in the testing set.ConclusionsIn conclusion, the predictive model for predicting liver cirrhosis in WD, constructed by machine learning, had a higher accuracy. And the most important indices in the predictive model were P-LCC, RDW-CV, serum ceruloplasmin, age at diagnosis, and MCV.

Polarized trafficking and copper transport activity of ATP7B: A mutational approach to establish genotype-phenotype correlation in Wilson disease.

Mutation in ATP7B gene causes Wilson disease (WD) that is characterized by severe hepatic and neurological symptoms. ATP7B localizes at the trans-Golgi Network (TGN) transporting copper to copper-dependent enzymes and traffics in apically targeted vesicles upon intracellular copper elevation. To decode the cellular underpinnings of WD manifestation we investigated copper-responsive polarized trafficking and copper transport activity of 15 WD causing point mutations in ATP7B. Amino-terminal mutations Gly85Val, Leu168Pro, and Gly591Asp displayed TGN and subapical localization whereas, Leu492Ser mislocalized at the basolateral region. The actuator domain mutation Gly875Arg shows retention in the endoplasmic reticulum (ER), Ala874Val and Leu795Phe show partial targeting to TGN and post-Golgi vesicles. The nucleotide-binding domain mutations His1069Gln and Leu1083Phe also display impaired targeting. The C-terminal mutations Leu1373Pro/Arg is arrested at ER but Ser1423Asn shows TGN localization. Transmembrane mutant Arg778Leu resides in ER and TGN while Arg969Gln is exclusively ER localized. Cellular Cu level does not alter the targeting of any of the studied mutations. Mutants that traffic to TGN exhibits biosynthetic function. Finally, we correlated cellular phenotypes with the clinical manifestation of the two most prevalent mutations; the early onset and more aggressive WD caused by Arg778Leu and the milder form of WD caused by mutation His1069Gln.

High value of 64Cu as a tool to evaluate the restoration of physiological copper excretion after gene therapy in Wilson’s disease

Wilson’s disease (WD) is an inherited disorder of copper metabolism associated with mutations in ATP7B gene. We have shown that the administration of an adeno-associated vector (AAV) encoding a mini version of human ATP7B (VTX-801) provides long-term correction of copper metabolism in a murine WD model. In preparation of a future clinical trial, we have evaluated by positron emission tomography (PET) the value of 64Cu biodistribution, excretion pattern, and blood kinetics as pharmacodynamic biomarkers of VTX-801 effects. Six-week-old WD mice were injected intravenously with increasing doses of VTX-801 and 3 weeks or 3 months later with [64Cu]CuCl2. Untreated WD and wild-type (WT) mice were included as controls. Control WD mice showed increased hepatic 64Cu retention, reduced fecal excretion of the radiotracer, and altered 64Cu blood kinetics (BK) compared with WT mice. VTX-801 treatment in WD mice resulted in a significant reduction of hepatic 64Cu accumulation, the restoration of fecal 64Cu excretion, and the correction of 64Cu BK. This study showed that VTX-801 restores physiological copper metabolism in WD mice, confirming the mechanism of action of VTX-801, and demonstrated the translational potential of [64Cu]CuCl2-PET to explore VTX-801 pharmacodynamics in a minimally invasive and sensitive manner in WD patients.

ATP7B gene therapy of autologous reprogrammed hepatocytes alleviates copper accumulation in a mouse model of Wilson's disease.

Wilson's disease (WD) is a rare hereditary disorder due to ATP7B gene mutation, causing pathologic copper storage mainly in the liver and neurological systems. Hepatocyte transplantation showed therapeutic potential; however, this strategy is often hindered by a shortage of quality donor cells and by allogeneic immune rejection. In this study, we aimed to evaluate the function and efficacy of autologous reprogrammed, ATP7B gene-restored hepatocytes using a mouse model of WD. Sufficient liver progenitor cells (LPCs) were harvested by reprogramming hepatocytes from ATP7B-/- mice with small molecules, which exhibited strong proliferation and hepatic differentiation capacity in vitro. After lentivirus-mediated mini ATP7B gene transfection and redifferentiation, functional LPC-ATP7B-derived hepatocytes (LPC-ATP7B-Heps) were developed. RNA sequencing data showed that, compared with LPC-green fluorescent protein-Heps (LPC-GFP-Heps) with enrichment of genes that were mainly in pathways of oxidative stress and cell apoptosis, in LPC-ATP7B-Heps under high copper stress, copper ion binding and cell proliferation pathways were enriched. LPC-ATP7B-Heps transplantation into ATP7B-/- mice alleviated deposition of excess liver copper with its associated inflammation and fibrosis, comparable with those observed using normal primary hepatocytes at 4 months after transplantation. We established a system of autologous reprogrammed WD hepatocytes and achieved ATP7B gene therapy in vitro. LPC-ATP7B-Heps transplantation demonstrated therapeutic efficacy on copper homeostasis in a mouse model of WD.

Phenotypes and ATP7B gene variants in 316 children with Wilson disease

Objectives: To summarize the clinical phenotypes and the variation spectrum of ATP7B gene in Chinese children with Wilson's disease (WD) and to investigate their significance for early diagnosis. Methods: Retrospective analysis was performed on the clinical data of 316 children diagnosed as WD in Guangzhou Women and Children's Medical Center during the period from January 2010 to June 2021. The general situations, clinical manifestations, lab test results, imaging examinations, and ATP7B gene variant characteristics were collected. The patients were divided into asymptomatic WD group and symptomatic WD group based on the presence or absence of clinical symptoms at the time that WD diagnosis was made. The χ2 test, t test or Mann-Whitney U test were used to compare the differences between groups. Results: Among the 316 children with WD, 199 were males and 117 were females, with the age of 5.4 (4.0, 7.6) years at diagnosis; 261 cases (82.6%) were asymptomatic with the age of 4.9 (3.9, 6.4) years; whereas 55 cases (17.4%) were symptomatic with the age of 9.6 (7.3, 12.0) years. The main symptoms invloved liver, kidney, nervous system, or skin damage. Of all the patients, 95.9% (303/316) had abnormal liver function at diagnosis; 98.1% (310/316) had the serum ceruloplasmin lever lower than 200 mg/L; 97.7% (302/309) had 24-hour urine copper content exceeding 40 μg; only 7.4% (23/310) had positive corneal K-F rings, 8.2% (23/281) had abnormal MRI signals in the lenticular nucleus, and all of them had symptoms of damage in liver, kidney or nervous system. Compared with the group of symptomatic WD, asymptomatic group had higher levels of serum alanine aminotransferase and lower levels ceruloplasmin and 24-hour urine copper [(208±137) vs. (72±78) U/L, (55±47) vs. (69±48) mg/L, 103 (72, 153) vs. 492 (230, 1 432) μg; t=9.98, -1.98, Z=-4.89, all P<0.001]. Among the 314 patients completing genetic sequencing, a total of 107 mutations in ATP7B gene were detected, of which 10 are novel variants, and 3 cases (1.0%) had large heterozygous deletion (exons 10 to exon 11) in ATP7B gene. The percentage of missense mutation in asymptomatic WD children was significantly higher than that in symptomatic WD (81.5% (422/518) vs. 69.1% (76/110), χ²=8.47, P<0.05). WD patients carrying homozygous variant of c.2 333G>T had significantly low levels of ceruloplasmin than those not carrying this variant ((23±5) vs. (61±48) mg/L, t=-2.34, P<0.001). Conclusions: The elevation of serum ALT is an important clue for early diagnosis of WD in children, while serum ceruloplasmin and 24-hour urine copper content are specific markers for early diagnosis of WD. In order to confirm the diagnosis of WD, it is necessary to combine the Sanger sequencing with multiplex ligation-dependent probe amplification or other testing technologies.

Wilson's Disease Update: An Indian Perspective.

Wilson's disease (WD) is an autosomal recessive disorder due to ATP7B gene mutation, resulting in defective copper metabolism, with liver and brain being primarily affected. Being a treatable disorder, early diagnosis and proper management of WD may result in near complete recovery. It has received significant attention over the past 50 years, with several Indian contributions. This study collates published Indian studies on WD in Pubmed and Embase databases and puts them in perspective. Several Indian case series suggest that WD may be more prevalent than thought. Commonly detected ATP7B mutation in India is p.C271X. Although initial Indian series reported significant osseomuscular presentation, neuropsychiatric and hepatic manifestations dominated the later reports. A significant male predominance is observed in Indian series. Pure hepatic presentation starts earlier than neurological or osseomuscular WD. A positive family history may be seen in nearly 50% of Indian WD cases with a high rate of consanguinity. Up to two-third of Indian cases may be initially misdiagnosed, with a mean diagnostic delay of up to 2 years. Abnormalities in serum ceruloplasmin and 24-hour urinary copper has been reported in more than four-fifth cases. Brain MRI is abnormal in nearly all neurological WD cases. Copper chelation remains the mainstay of therapy, with D-penicillamine being the most widely used chelator in India. Global Assessment Scale for WD is a comprehensive tool for clinical monitoring. Hepatic presentation carries a five-time higher mortality risk than neurological, with up to 90% Indian neurological WD cases recovering to pre-morbid functionality with adequate therapy.