Distinct clinical courses according to presenting phenotypes and their correlations to ATP7B mutations in a large Wilson's disease cohort

Plasma exchange improves survival with native liver in Wilson disease with new Wilson's index ≥ 11 & early hepatic encephalopathy

BACKGROUND AND AIM

Decision about liver transplant is difficult in Wilson disease (WD) with liver failure, especially with conflicting reports about new Wilson index (NWI). Therapeutic plasma exchange (TPE) can provide survival with native liver (SNL) in WD. This study was done to see the effect of TPE on outcome and identify factors for SNL.

METHODS

All cases of WD with liver failure (INR. ≥ 2.5) from prospectively maintained data were included for propensity score matching (PSM) to select TPE (n = 48) and no-TPE (n = 48) groups. Three sessions of TPE on three consecutive days were given to TPE group.

RESULTS

One hundred fifty-nine cases were included in the PSM with NWI & hepatic encephalopathy (HE) grading as predictors. SNL was comparable (26 vs. 17 cases (OR 1.45, p = 0.05) when the analysis was done in the whole cohort of 96 patients. SNL significantly improved when performed in those with no to early HE: TPE group (24/37) versus no-TPE group (14/34) (OR = 1.70, p = 0.03). Kaplan-Meier survival curves were significantly (log rank 0.019) improved in the TPE group when analyzing in no to early HE. Lower INR (adjusted OR 0.47, 95%CI 0.28-0.79, p = 0.005) and TPE administration (adjusted OR 3.12, 95%CI 1.10-9.4, p = 0.032) at enrollment were independently associated with SNL. Lower NWI (adjusted OR 0.686, 95%CI 0.53-0.89, p = 0.005) at 96 h was independently associated with SNL.

CONCLUSIONS

TPE is independently associated with improvement in SNL by threefold in patients with NWI ≥ 11 and no to early HE. Patients with advanced HE should be offered immediate liver transplant. After 3 sessions of TPE, NWI < 11 increases SNL by 32%. Hence, NWI should be maintained below 11 with more sessions of TPE.

Spectrum of Pathogenic Variants of the ATP7B Gene and Genotype-Phenotype Correlation in Eastern Eurasian Patient Cohorts with Wilson's Disease

Background/Objectives: Wilson's disease (WD) (OMIM 277900) or hepatolenticular degeneration is an autosomal recessive disorder caused by impaired copper excretion with subsequent accumulation in the liver, brain, and other tissues of the body. The defects in copper metabolism are based on various pathogenic variants of the ATP7B gene encoding copper-transporting P-type ATPase. The aim of this work is to search for pathogenic variants of the ATP7B gene among Eastern Eurasian patient cohorts and to pick correlations between pathogenic variants, gender, age of onset of the disease, and the course of the disease. Methods: The material for the study was the biomaterial of 100 people. The search for mutations was carried out by Sanger sequencing. Multiple alignment of nucleotide sequences and their analysis was performed using the MEGA-X software. To study the genotype-phenotypic correlation, an analysis of the medical records of each patient was carried out. Results: Most common pathogenic variant (48%) in the sample is p.His1069Gln (c.3207C>A), located in exon 14 of the ATP7B gene. Pathogenic variants of p.Glu1064Lys (c.3190G>A)-20%-and p.Met769HisfsTer26 (c.2304insC)-8%-of exons 14 and 8 were also common. For patients with pathogenic alleles p.His1069Gln (c.3207C>A) and p.Glu1064Lys (c.3190G>A), typical deviations are mental and neurological manifestations of WD. In patients with the pathogenic allele p.Met769HisfsTer26 (c.2304insC), deviations are more characteristic of the liver and a combination of various symptoms that are atypical for WD. Conclusions: In this study, we were able to obtain differences in symptoms in patients with different pathogenic alleles of the ATP7B gene.

Portal hypertension and its prognostic implications in patients with Wilson's disease

BACKGROUND AND AIMS

Wilson's disease may progress to cirrhosis and clinically significant portal hypertension (CSPH). We aimed to assess the prevalence and prognostic impact of CSPH-related features on hepatic decompensation and transplant-free survival in patients with Wilson's disease.

METHODS AND RESULTS

About 137 patients with Wilson's disease (Leipzig score ≥4), followed for a median observation period of 9.0 (3.9-17.7) years at the Vienna General Hospital, were included in this retrospective study. Overall, 49 (35.8%) developed features of CSPH: 14 (10.2%) varices, 40 (29.2%) splenomegaly, 20 (14.6%) ascites, 18 (13.1%) hepatic encephalopathy and 3 (2.2%) experienced acute variceal bleeding. Overall, 8 (5.8%) patients died, including three deaths caused by CSPH-related complications. Within 10 years, compensated patients with features of CSPH developed more decompensation events (8.3% vs. 1.5% in patients without CSPH, p = 0.3) and had worse transplant-free-survival (91.7% vs. 98.6%), which further declined in patients with hepatic decompensation (26.7%, log-rank: p < 0.0001). Patients with liver stiffness <15 kPa and normal platelets (≥150 G/L) were less likely to decompensate within 10 years (2.6% vs. 8.4%, p = 0.002) and had a better 10-year transplant-free-survival (97.7% vs. 83.9%, p = 0.006).

CONCLUSIONS

Patients with Wilson's disease developing features of CSPH are at an increased risk for hepatic decompensation and liver-related mortality, warranting for regular screening and timely initiation of effective CSPH-directed treatments.

Wilson disease: the diagnostic challenge and treatment outcomes in a series of 262 cases

BACKGROUND

 Wilson disease (WD) is an autosomal recessive disorder that leads to organ toxicity due to copper overload. Early diagnosis is complicated by the rarity and diversity of manifestations.

OBJECTIVE

 To describe the diagnostic features and response to treatment in our cohort of WD patients.

METHODS

 This was a retrospective analysis of 262 WD patients stratified by clinical presentation, complementary exams, ATP7B genotyping, and response to treatment.

RESULTS

 Symptoms occurred at an average age of 17.4 (7-49) years, and patients were followed up for an average of 9.6 (0-45) years. Patients presented mainly with hepatic (36.3%), neurologic (34.7%), and neuropsychiatric (8.3%) forms. Other presentations were hematologic, renal, or musculoskeletal, and 16.8% of the patients were asymptomatic. Kayser-Fleischer rings occurred in 78.3% of the patients, hypoceruloplasminemia in 98.3%, and elevated cupruria/24h in 73.0%, with an increase after D-penicillamine in 54.0%. Mutations of the ATP7B gene were detected in 84.4% of alleles. Brain magnetic resonance imaging showed abnormalities in the basal ganglia in 77.7% of patients. D-penicillamine was the first choice in 93.6% of the 245 patients, and 21.1% of these patients were switched due to adverse effects. The second-line therapies were zinc and trientine. The therapeutic response did not differ significantly between the drugs (p = 0.2). Nine patients underwent liver transplantation and 82 died.

CONCLUSION

 Wilson disease is diagnosed at a late stage, and therapeutic options are limited. In people under 40 years of age with compatible manifestations, WD could be considered earlier in the differential diagnosis. There is a need to include ATP7B genotyping and therapeutic alternatives in clinical practice.

Structure and mechanism of the human copper transporting ATPases: Fitting the pieces into a moving puzzle

Human copper transporters ATP7B and ATP7A deliver copper to biosynthetic pathways and maintain copper homeostasis in the cell. These enzymes combine several challenges for structural biology because they are large low abundance membrane proteins with many highly mobile domains and long disordered loops. No method has yet succeeded in solving the structure of the complete fully functional protein. Still, X-ray crystallography, Cryo-EM and NMR helped to piece together a structure based model of the enzyme activity and regulation by copper. We review the structures of ATP7B and ATP7A with an emphasis on the mechanistic insights into the unique aspects of the transport function and regulation of the human copper ATPases that have emerged from more than twenty years of research.

Clinical, biochemical and molecular characterization of Wilson's disease in Moroccan patients

Background

Wilson Disease (WD) is an autosomal recessive inherited metabolic disease caused by mutations in the ATP7B gene. WD is characterized by heterogeneous clinical presentations expressed by hepatic and neuropsychiatric phenotypes. The disease is difficult to diagnose, and misdiagnosed cases are commonly seen.

Methods

In this study, the presented symptoms of WD, the biochemical parameters as well as its natural history are described based on cases collected in Mohammed VI Hospital University of Marrakech (Morocco). We screened and sequenced 21 exons of ATP7B gene from 12 WD patients that confirmed through biochemical diagnosis.

Results

Mutational assessment of the ATP7B gene showed six homozygous mutations in 12 individuals however, 2 patients had no evidence of any mutation in promoter and exonic regions. All mutations are pathogenic and most were missense mutations. c.2507G > A (p.G836E), c.3694A > C (p.T1232P) and c.3310 T > C (p.C1104R) that were identified in 4 patients. The other mutations were a non-sense mutation (c.865C > T (p.C1104R)) detected in 2 patients, a splice mutation (c.51 + 4A > T) detected in 2 patients and a frameshift mutation (c.1746 dup (p.E583Rfs*25) detected in 2 patients.

Conclusion

Our study is the first molecular analysis in Moroccan patients with Wilson's disease, the ATP7B mutational spectrum in the Moroccan population is diverse and still unexplored.

Genetic Movement Disorders Commonly Seen in Asians

The increasing availability of molecular genetic testing has changed the landscape of both genetic research and clinical practice. Not only is the pace of discovery of novel disease-causing genes accelerating but also the phenotypic spectra associated with previously known genes are expanding. These advancements lead to the awareness that some genetic movement disorders may cluster in certain ethnic populations and genetic pleiotropy may result in unique clinical presentations in specific ethnic groups. Thus, the characteristics, genetics and risk factors of movement disorders may differ between populations. Recognition of a particular clinical phenotype, combined with information about the ethnic origin of patients could lead to early and correct diagnosis and assist the development of future personalized medicine for patients with these disorders. Here, the Movement Disorders in Asia Task Force sought to review genetic movement disorders that are commonly seen in Asia, including Wilson's disease, spinocerebellar ataxias (SCA) types 12, 31, and 36, Gerstmann-Sträussler-Scheinker disease, PLA2G6-related parkinsonism, adult-onset neuronal intranuclear inclusion disease (NIID), and paroxysmal kinesigenic dyskinesia. We also review common disorders seen worldwide with specific mutations or presentations that occur frequently in Asians.

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.

Missing heritability of Wilson disease: a search for the uncharacterized mutations

Wilson disease (WD), a copper metabolism disorder caused by mutations in ATP7B, manifests heterogeneous clinical features. Interestingly, in a fraction of clinically diagnosed WD patients, mutations in ATP7B appears to be missing. In this review we discuss the plausible explanations of this missing heritability and propose a workflow that can identify the hidden mutations. Mutation analyses of WD generally includes targeted sequencing of ATP7B exons, exon-intron boundaries, and rarely, the proximal promoter region. We propose that variants in the distal cis-regulatory elements and/or deep intronic variants that impact splicing might well represent the hidden mutations. Heterozygous del/ins that remain refractory to conventional PCR-sequencing method may also represent such mutations. In this review, we also hypothesize that mutations in the key copper metabolism genes, like, ATOX1, COMMD1, and SLC31A1, could possibly lead to a WD-like phenotype. In fact, WD does present overlapping symptoms with other rare genetic disorders; hence, the possibility of a misdiagnosis and thus adding to missing heritability cannot be excluded. In this regard, it seems that whole-genome analysis will provide a comprehensive and rapid molecular diagnosis of WD. However, considering the associated cost for such a strategy, we propose an alternative customized screening schema of WD which include targeted sequencing of ATP7B locus as well as other key copper metabolism genes. Success of such a schema has been tested in a pilot study.

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.

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.

Genotype-phenotype variable correlation in Wilson disease: clinical history of two sisters with the similar genotype

BACKGROUND

Wilson disease (WD) is an Autosomal-Recessive disorder due to mutations of ATP7B gene on chromosome 13q14.3. Inadequate protein function leads to low ceruloplasmin blood levels and copper accumulation in liver, basal ganglia and chornea. Main clinical manifestations are hypertransaminasemia, tremors, dysarthria, dystonia and psychiatric symptoms. The phenotypic variability in WD is considerable and its onset can be heterogeneous: the most common type in childhood is the hepatic involvement, followed by the neurological one or others. The presence of a genotype-phenotype correlation has not yet been fully demonstrated. The phenotypic variability may be explained by the intervention of other modifier genes regulating copper metabolism in the presence of mutations ATP7B.

CASE PRESENTATION

A streaking phenotypic variability was observed in two Sicilian sisters carrying the same genotype for ATB7B gene [c.3207C > A / c.3904-2A > G]. Although both started to present signs at age 10 years, onset was characterized by neurological signs in the first (tremors, motor incoordination, language and cognitive impairment), while liver involvement has been the only sign in the other. They started the same chelation therapy. After a 20-year follow-up the former is severely affected (MRI evidence of basal ganglia copper deposits and hyperchogenic liver, thrombocytopenia), while the latter presents only a moderate liver enlargement. In literature, the splice mutation c.3904-2A > G is also reported in Egypt population, associated with acute liver failure or chronic hepatic disease, and it could be typical of Mediterranean area, not being reported in other geographical zones.

CONCLUSION

Based on our clinical experience in Eastern Sicily, there is a considerable phenotypic variability in WD, even in the presence of an identical genotype. The mutation c.3904-2A > G could be associated with this phenotypic variability in Mediterranean population, but further studies should be conducted. This condition could be explained by the intervention of modifier genes regulating copper metabolism in the presence of defective ATP7B protein function. Further investigations on their role by Next Generation Sequencing or Whole Exome Analysis might have a profound impact on patients' management and in particular on therapy.

Wilson disease missense mutations in ATP7B affect metal-binding domain structural dynamics

Wilson disease (WD) is caused by mutations in the gene for ATP7B, a copper transport protein that regulates copper levels in cells. A large number of missense mutations have been reported to cause WD but genotype-phenotype correlations are not yet established. Since genetic screening for WD may become reality in the future, it is important to know how individual mutations affect ATP7B function, with the ultimate goal to predict pathophysiology of the disease. To begin to assess mechanisms of dysfunction, we investigated four proposed WD-causing missense mutations in metal-binding domains 5 and 6 of ATP7B. Three of the four variants showed reduced ATP7B copper transport ability in a traditional yeast assay. To probe mutation-induced structural dynamic effects at the atomic level, molecular dynamics simulations (1.5 μs simulation time for each variant) were employed. Upon comparing individual metal-binding domains with and without mutations, we identified distinct differences in structural dynamics via root-mean square fluctuation and secondary structure content analyses. Most mutations introduced distant effects resulting in increased dynamics in the copper-binding loop. Taken together, mutation-induced long-range alterations in structural dynamics provide a rationale for reduced copper transport ability.

Age and Sex but Not ATP7B Genotype Effectively Influence the Clinical Phenotype of Wilson Disease

Wilson disease (WD) is an inherited disorder of hepatic copper metabolism with considerable variation in clinical presentations, the most common ones being liver disease and neuropsychiatric disturbances. This study investigated the clinical presentation in relation to mutations in a large cohort of patients with WD. A total of 1,357 patients (702 children, 655 adults; 1,172 index patients, 185 siblings, all with a Leipzig score ≥4, male/female: 679/678) were studied. The age and the symptoms at presentation were used as key phenotypic markers. Index patients were clinically classified as having either hepatic (n = 711) or neurologic disease (n = 461). Seven hundred fifteen (52.7%) patients had a liver biopsy at diagnosis. DNA was sequenced by the Genetic Analyzers ABI Prism 310 (Perkin Elmer) or 3500 (Applied Biosystems). Three hundred ninety-four different mutation combinations were detected. The most frequent mutation was H1069Q (c.3207C>A; allele frequency: 46.9%), followed by P767P-fs (c.2304dupC; 2.85%), P1134P-fs (c.3402delC; 2.8%), and R969Q (c.2755C>T; 2.18%). There was no correlation between mutations and individual clinical manifestation. There was a gender effect in index patients: Hepatic presentation was more common in females (male/female: 328/383) and neurologic presentation in males (259/202; P < 0.001). At diagnosis, 39.5% of children/adolescents (≤18 years) and 58% of adults already had cirrhosis. The presence of cirrhosis did not correlate with the genotype. Conclusion: These findings refine and extend our understanding of the natural history and individual spectrum/manifestations of WD. Initially, there is asymptomatic hepatic involvement, which may progress and become symptomatic. Neurologic symptoms present many years later.

Wilson's Disease: Clinical Practice Guidelines of the Indian National Association for Study of the Liver, the Indian Society of Pediatric Gastroenterology, Hepatology and Nutrition, and the Movement Disorders Society of India

Clinical practice guidelines for Wilson's disease (WD) have been published by the American Association for the Study of Liver Diseases and European Association for the Study of the Liver in 2008 and 2012, respectively. Their focus was on the hepatic aspects of the disease. Recently, a position paper on pediatric WD was published by the European Society of Pediatric Gastroenterology Hepatology and Nutrition. A need was felt to harmonize guidelines for the hepatic, pediatric, and neurological aspects of the disease and contextualize them to the resource-constrained settings. Therefore, experts from national societies from India representing 3 disciplines, hepatology (Indian National Association for Study of the Liver), pediatric hepatology (Indian Society of Pediatric Gastroenterology, Hepatology and Nutrition), and neurology (Movement Disorders Society of India) got together to evolve fresh guidelines. A literature search on retrospective and prospective studies of WD using MEDLINE (PubMed) was performed. Members voted on each recommendation, using the nominal voting technique. The Grades of Recommendation, Assessment, Development and Evaluation system was used to determine the quality of evidence. Questions related to diagnostic tests, scoring system, and its modification to a version suitable for resource-constrained settings were posed. While ceruloplasmin and 24-h urine copper continue to be important, there is little role of serum copper and penicillamine challenge test in the diagnostic algorithm. A new scoring system - Modified Leipzig score has been suggested with extra points being added for family history and serum ceruloplasmin lower than 5 mg/dl. Liver dry copper estimation and penicillamine challenge test have been removed from the scoring system. Differences in pharmacological approach to neurological and hepatic disease and global monitoring scales have been included. Rising bilirubin and worsening encephalopathy are suggested as indicators predicting need for liver transplant but need to be validated. The clinical practice guidelines provide recommendations for a comprehensive management of WD which will be of value to all specialties.

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.

Multiplex Ligation-dependent Probe Amplification Analysis Subsequent to Direct DNA Full Sequencing for Identifying ATP7B Mutations and Phenotype Correlations in Children with Wilson Disease

BACKGROUND

Mutations in ATP7B cause Wilson disease (WD). However, direct DNA full sequencing cannot detect all mutations in patients with WD. Multiplex ligation-dependent probe amplification (MLPA) analysis is reportedly useful in increasing the diagnostic yield in other genetic disorders with large deletions or insertions. The aim of this study was to evaluate whether the detection rate of ATP7B mutations can be increased by using MLPA.

METHODS

We enrolled 114 children with WD from 104 unrelated families based on biochemical tests and direct DNA full sequencing. The patients with one or zero mutant allele were investigated using MLPA. We analyzed phenotypic correlations.

RESULTS

Total allele frequency by full sequencing was 87.5%. Full sequencing revealed two mutant alleles in 80 of 104 unrelated children. One mutant allele was detected in 22 children, and no mutations were found in two children. Novel mutations including small deletions with frameshift mutations were identified by DNA sequencing. MLPA revealed no gross deletion or duplication in 24 children with one or zero mutant alleles. The number of detected mutations was not associated with hepatic manifestation, age of onset, Kayser-Fleischer ring, ceruloplasmin, and urinary Cu concentrations.

CONCLUSION

MLPA showed a limited role to increase the mutation detection rate in children who do not receive a definite genetic diagnosis of WD through DNA full sequencing. This finding suggests that large deletions or duplications might be extremely rare in WD. Further development is needed to improve the genetic diagnosis of WD.

The optimal threshold of serum ceruloplasmin in the diagnosis of Wilson's disease: A large hospital-based study

Background and aims

A ceruloplasmin (CP) concentration <200 mg/L is conventionally considered as one of the major diagnostic criteria for Wilson’s disease (WD). However, the diagnostic accuracy of this threshold has never been investigated in a sufficiently large group of patients. This study aims to present the results of serum CP measurements in various patients and to identify the optimal cutoff value of CP for the diagnosis of WD.

Materials and methods

We identified patients whose CP levels were evaluated from January 1, 2016 to December 31, 2016 using a laboratory information database. Data related to CP measurement were retrieved. We carefully reviewed patients’ electronic medical records to correct errors and to obtain other necessary data. Data related to WD were retrieved from a special document containing medical records of patients with WD, which were created, modified, and maintained by authors.

Results

CP level was determined in 4048 patients (WD, 297; non-WD, 3751). The mean serum CP level in patients with WD was 50.6±44.2 mg/L, which was significantly lower than that in non-WD patients (293.2±117.3 mg/L, p<0.001). Only 1.0% of patients with WD had CP ≥200 mg/L. The sensitivity and specificity of CP for the diagnosis of WD were 99.0 and 80.9%, respectively, for the conventional cutoff value <200 mg/L and 95.6 and 95.5%, respectively, for the cutoff value <150 mg/L; the latter provided a higher diagnostic accuracy for WD. 53.0% of patients with liver failure, 37.7% of patients with nephrotic syndrome, and 23.0% of patients age 1 to 6 months had serum CP <200 mg/L. Patients who were pregnant and those with malignant tumors, and infectious and inflammatory diseases had significantly higher mean serum CP levels.

Conclusion

The optimal cutoff value of CP for the diagnosis of WD in China is 150 mg/L, with a sensitivity of 95.6% and specificity of 95.5%, thereby providing the highest diagnostic accuracy for WD.

Development and evaluation of an unlabeled probe high-resolution melting assay for detection of ATP7B mutations in Wilson's disease

BACKGROUND

Wilson's disease (WD) is a rare autosomal recessive disorder characterized by the deposition of copper mainly in the liver or nerve system that leads to their dysfunction. Mutations in the gene encoding ATPase, Cu+ transporting, beta polypeptide (ATP7B) are causative for WD. The aim of this study was to develop a rapid and convenient assay for detection of the three most common causative ATP7B mutations, p.R778L, p.P992L, and p.V1106I.

METHODS

Plasmids containing DNA fragments harboring each of the three ATP7B mutations were constructed. High-resolution melting (HRM) analysis was conducted by asymmetric polymerase chain reaction (PCR) amplification with paired primer and unlabeled probe, performed in a 96-well plate formatted LightCycler 480 Real-Time PCR System. The assay was evaluated for accuracy and reproducibility by genotyping of 41 WD cases.

RESULTS

The unlabeled probe HRM assays performed on constructs with the p.R778L, p.P992L, and p.V1106I mutations in the ATP7B gene resulted in additional melting peaks. According to the unlabeled probe HRM molecular signature, we could differentiate homozygous mutations from wild-type with the ΔTm (difference between melting temperatures) >4°C, and the coefficient of variation in repeatability tests was <5%. In the validation assay using our method to examine clinical samples, a 100% accuracy rate was achieved.

CONCLUSIONS

The newly developed assay to rapidly genotype the ATP7B mutations is convenient, accurate, and reproducible, and represents a favorable alternative to Sanger sequencing in the identification of specific ATP7B mutations.

The Menkes and Wilson disease genes counteract in copper toxicosis in Labrador retrievers: a new canine model for copper-metabolism disorders

The deleterious effects of a disrupted copper metabolism are illustrated by hereditary diseases caused by mutations in the genes coding for the copper transporters ATP7A and ATP7B. Menkes disease, involving ATP7A, is a fatal neurodegenerative disorder of copper deficiency. Mutations in ATP7B lead to Wilson disease, which is characterized by a predominantly hepatic copper accumulation. The low incidence and the phenotypic variability of human copper toxicosis hamper identification of causal genes or modifier genes involved in the disease pathogenesis. The Labrador retriever was recently characterized as a new canine model for copper toxicosis. Purebred dogs have reduced genetic variability, which facilitates identification of genes involved in complex heritable traits that might influence phenotype in both humans and dogs. We performed a genome-wide association study in 235 Labrador retrievers and identified two chromosome regions containing ATP7A and ATP7B that were associated with variation in hepatic copper levels. DNA sequence analysis identified missense mutations in each gene. The amino acid substitution ATP7B:p.Arg1453Gln was associated with copper accumulation, whereas the amino acid substitution ATP7A:p.Thr327Ile partly protected against copper accumulation. Confocal microscopy indicated that aberrant copper metabolism upon expression of the ATP7B variant occurred because of mis-localization of the protein in the endoplasmic reticulum. Dermal fibroblasts derived from ATP7A:p.Thr327Ile dogs showed copper accumulation and delayed excretion. We identified the Labrador retriever as the first natural, non-rodent model for ATP7B-associated copper toxicosis. Attenuation of copper accumulation by the ATP7A mutation sheds an interesting light on the interplay of copper transporters in body copper homeostasis and warrants a thorough investigation of ATP7A as a modifier gene in copper-metabolism disorders. The identification of two new functional variants in ATP7A and ATP7B contributes to the biological understanding of protein function, with relevance for future development of therapy.

Summary: Labrador retrievers with hereditary copper toxicosis are a useful new model for copper-metabolism disorders.

Recent advance in the molecular genetics of Wilson disease and hereditary hemochromatosis

Metabolic liver diseases such as Wilson disease (WD) and hereditary hemochromatosis (HH) possess complicated pathogenesis and typical hereditary characteristics with the hallmarks of a deficiency in metal metabolism. Mutations in genes encoding ATPase, Cu + transporting, beta polypeptide (ATP7B) and hemochromatosis (HFE) or several non-HFE genes are considered to be causative for WD and HH, respectively. Although the identification of novel mutations in ATP7B for WD and HFE or the non-HFE genes for HH has increased, especially with the application of whole genome sequencing technology in recent years, the biological function of the identified mutations, as well as genotype-phenotype correlations remain to be explored. Further analysis of the causative gene mutation would be critical to clarify the mechanisms underlying specific disease phenotypes. In this review, we therefore summarize the recent advances in the molecular genetics of WD and HH including the updated mutation spectrums and the correlation between genotype and phenotype, with an emphasis on biological functional studies of the individual mutations identified in WD and HH. The weakness of the current functional studies and analysis for the clinical association of the individual mutation was also discussed. These works are essential for the understanding of the association between genotypes and phenotypes of these inherited metabolic liver diseases.

Currently Clinical Views on Genetics of Wilson's Disease

Objective:

The objective of this study was to review the research on clinical genetics of Wilson's disease (WD).

Data Sources:

We searched documents from PubMed and Wanfang databases both in English and Chinese up to 2014 using the keywords WD in combination with genetic, ATP7B gene, gene mutation, genotype, phenotype.

Study Selection:

Publications about the ATP7B gene and protein function associated with clinical features were selected.

Results:

Wilson's disease, also named hepatolenticular degeneration, is an autosomal recessive genetic disorder characterized by abnormal copper metabolism caused by mutations to the copper-transporting gene ATP7B. Decreased biliary copper excretion and reduced incorporation of copper into apoceruloplasmin caused by defunctionalization of ATP7B protein lead to accumulation of copper in many tissues and organs, including liver, brain, and cornea, finally resulting in liver disease and extrapyramidal symptoms. It is the most common genetic neurological disorder in the onset of adolescents, second to muscular dystrophy in China. Early diagnosis and medical therapy are of great significance for improving the prognosis of WD patients. However, diagnosis of this disease is usually difficult because of its complicated phenotypes. In the last 10 years, an increasing number of clinical studies have used molecular genetics techniques. Improved diagnosis and prediction of the progression of this disease at the molecular level will aid in the development of more individualized and effective interventions, which is a key to transition from molecular genetic research to the clinical study.

Conclusions:

Clinical genetics studies are necessary to understand the mechanism underlying WD at the molecular level from the genotype to the phenotype. Clinical genetics research benefits newly emerging medical treatments including stem cell transplantation and gene therapy for WD patients.

ATP7B Gene Mutations in Croatian Patients with Wilson Disease

AIMS

Wilson disease (WD) is an autosomal recessive disorder of copper metabolism, characterized by its accumulation in tissues which results in hepatic, neurological, and/or psychiatric symptoms. The aim of this study was to investigate the genetics of WD in Croatian patients.

METHODS

Correlation of the clinical presentation subtype and the age at onset of the diagnosis of WD with the ATP7B genotype was investigated in a group of Croatian WD patients. DNA from peripheral blood samples was tested for the p.His1069Gln by direct mutational analysis and other polymorphisms were identified by sequence analysis of coding and flanking intronic regions of ATP7B gene.

RESULTS

In the group of 75 WD patients of Croatian origin, 18 different mutations in ATP7B gene were detected, three of which were novel. The p.His1069Gln mutation was most frequent, being detected in 44 Croatian WD patients (58.7%). Most ATP7B mutations (90.4%) were located in exons 5, 8, 13, 14, and 15.

CONCLUSIONS

Clinical diagnosis of WD was confirmed in 59 patients by detecting mutations on both ATP7B alleles. The age at onset of WD and the type of WD clinical presentation showed no significant correlation with the ATP7B genotype.

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.

Wilson's disease: a comprehensive review of the molecular mechanisms

Wilson's disease (WD), also known as hepatolenticular degeneration, is an autosomal recessive inherited disorder resulting from abnormal copper metabolism. Reduced copper excretion causes an excessive deposition of the copper in many organs such as the liver, central nervous system (CNS), cornea, kidney, joints, and cardiac muscle where the physiological functions of the affected organs are impaired. The underlying molecular mechanisms for WD have been extensively studied. It is now believed that a defect in P-type adenosine triphosphatase (ATP7B), the gene encoding the copper transporting P-type ATPase, is responsible for hepatic copper accumulation. Deposited copper in the liver produces toxic effects via modulating several molecular pathways. WD can be a lethal disease if left untreated. A better understanding of the molecular mechanisms causing the aberrant copper deposition and organ damage is the key to developing effective management approaches.

Liver transplantation for metabolic liver disease: experience at a living donor dominant liver transplantation center

PURPOSE

Metabolic liver disease (MLD) often progresses to life-threatening conditions. This study intends to describe the outcomes of liver transplantation (LTx) for MLD at a living donor-dominant transplantation center where potentially heterozygous carrier grafts are employed.

METHODS

We retrospectively evaluated the medical records of 54 patients with MLD who underwent LTx between November 1995 and February 2012 at Asan Medical Center in Seoul, Korea. The cumulative graft and patient survival rates were analyzed according to patient age, and living or deceased donor LTx. Recurrence of the original disease was also investigated.

RESULTS

The post-transplant cumulative patient survival rates at one, five, and 10 years were 90.7%, 87.5% and 87.5%, and the graft survival rates were 88.8%, 85.5%, and 85.5%, respectively. There were no differences in the patient survival rates according to the recipient age, human leukocyte antigen matching, and living or deceased donor LTx. There were also no differences in the patient survival rates between the MLD and the non-MLD groups for children. Recurrence of the original metabolic disease was not observed in any patient during the follow-up period.

CONCLUSION

Our results suggest that the living donor-dominant transplantation program is well-tolerated in MLD without recurrence of the original MLD using all types of transplantation.

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.

Update on Wilson disease

Wilson disease (WD) is an inherited disorder of chronic copper toxicosis characterized by excessive copper deposition in the body, primarily in the liver and the brain. It is a progressive disease and fatal if untreated. Excessive copper accumulation results from the inability of liver to excrete copper in bile. Copper is an essential trace metal and has a crucial role in many metabolic processes. Almost all of the body copper is protein bound. In WD, the slow but relentless copper accumulation overwhelms the copper chaperones (copper-binding proteins), resulting in high levels of free copper and copper-induced tissue injury. Liver is the central organ for copper metabolism, and copper is initially accumulated in the liver but over time spills to other tissues. WD has protean clinical manifestations mainly attributable to liver, brain, and osseomuscular impairment. Diagnosis of WD is challenging and based on combination of clinical features and laboratory tests. Identification of various high-frequency mutations identified in different population studies across the world has revived interest in developing DNA chips for rapid genetic diagnosis of WD. All symptomatic and all presymptomatic patients require lifelong decoppering with careful clinical tracking. Decoppering ensures that presymptomatic individuals remain symptom free. With judicious decoppering, given time, even patients with severe neurological disability improve and can return to normal life and resume school or work at par with their peers. Treatment regimens and tracking patients using the WD-specific Global Assessment Scale for WD (GAS for WD) are discussed.

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.

Phenotype-genotype correlations in patients with Wilson's disease

There is considerable phenotypic variation in Wilson's disease (WD). Some patients present with hepatic disease during the first decade of life and some with neurological degeneration in adolescence or adult life, with or without overt liver disease. Although the absence of neurologic disease in patients with liver disease in childhood or adolescence can be explained by the limited time exposure of the central nervous system to copper toxicity, it is surprising that late-onset neurologic WD can occur without any evidence of liver involvement. This huge variability in the clinical presentation of WD in general reflects our limited knowledge on the natural history of WD. Genetic association studies require the phenotype to be defined as accurately as possible.

Factors that predict mortality in children with Wilson disease associated acute liver failure and comparison of Wilson disease specific prognostic indices

BACKGROUND AND AIMS

Wilson disease (WD) associated acute liver failure (ALF) affects children more than adults. The predictors of mortality and outcome in patients without encephalopathy are not clear. We investigated the ability of prognostic factors and various models including model for end-stage liver disease (MELD) to predict mortality among children with WD and ALF.

METHODS

We analyzed the admission characteristics in 61 children <18 years with WD and ALF. Factors associated with mortality on univariate Cox regression analysis were analyzed by forward stepwise Cox hazards regression. The prognostic models such as Nazer's model, revised Kings College Model, and pediatric end-stage liver disease/model for end-stage liver disease (PELD/MELD) score were compared.

RESULTS

Of the 145 children < 18 years with WD, 61 experienced ALF of whom 33 (54%) died, including 22/27 (81.5%) with encephalopathy and 11/34 (32.4%) without encephalopathy. The mean age of children with ALF was 9.7 years, 38(62.3%) were boys. Prognostic factors significant for mortality included encephalopathy, international normalized ratio, total proteins, total and direct bilirubin, alkaline phosphatase, serum creatinine, and white blood cell count. Forward stepwise Cox proportional hazards regression identified encephalopathy (hazard ratio 2.88; CI 1.1-7.4) and total bilirubin (hazard ratio 1.05; CI: 1.02-1.09) as predictors of outcome. The area under the receiver operating curve (AUC) of the Nazer index, revised King's College Criteria, and PELD/MELD were 0.74, 0.76, and 0.75, respectively.

CONCLUSIONS

Mortality in children with WD and ALF is 54% including 81.5% with encephalopathy and 32.4% without encephalopathy. The prognostic models, MELD/PELD score, Nazer index and Kings College Criteria are comparable with a AUC between 0.74-0.76.

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.

Maternal choline modifies fetal liver copper, gene expression, DNA methylation, and neonatal growth in the tx-j mouse model of Wilson disease

Maternal diet can affect fetal gene expression through epigenetic mechanisms. Wilson disease (WD), which is caused by autosomal recessive mutations in ATP7B encoding a biliary copper transporter, is characterized by excessive hepatic copper accumulation, but variability in disease severity. We tested the hypothesis that gestational supply of dietary methyl groups modifies fetal DNA methylation and expression of genes involved in methionine and lipid metabolism that are impaired prior to hepatic steatosis in the toxic milk (tx-j) mouse model of WD. Female C3H control and tx-j mice were fed control (choline 8 mmol/Kg of diet) or choline-supplemented (choline 36 mmol/Kg of diet) diets for 2 weeks throughout mating and pregnancy to gestation day 17. A second group of C3H females, half of which were used to cross foster tx-j pups, received the same diet treatments that extended during lactation to 21 d postpartum. Compared with C3H, fetal tx-j livers had significantly lower copper concentrations and significantly lower transcript levels of Cyclin D1 and genes related to methionine and lipid metabolism. Maternal choline supplementation prevented the transcriptional deficits in fetal tx-j liver for multiple genes related to cell growth and metabolism. Global DNA methylation was increased by 17% in tx-j fetal livers after maternal choline treatment (P<0.05). Maternal dietary choline rescued the lower body weight of 21 d tx-j mice. Our results suggest that WD pathogenesis is modified by maternal in utero factors, including dietary choline.

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.

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.

Mutation analysis of ATP7B gene in Turkish Wilson disease patients: identification of five novel mutations

Wilson disease is an autosomal recessive disorder of copper metabolism caused by mutations in the ATP7B gene that encodes a P-type copper transporting ATPase. The aim of this study was to screen and detect mutations of the ATP7B gene in unrelated Turkish Wilson disease patients (n = 46) and control group (n = 52). Mutations were screened and detected by DNA sequencing. 30 out of 46 patients had mutations. 24 different Wilson disease related mutations were identified in those patients. The distribution of mutations in ATP7B gene was as follow: 17 missense, 3 nonsense, 1 silent, 3 frameshift (1 insertion, 2 deletion). None of them were not found in the control group. Five out of 24 mutations were found to be novel. Four of them were missense (c.2363C > T, c.3106G > A, c.3451C > T, c.3733C > A). The last one was deletion (c.3111delC). 10 single nucleotide polymorphisms (SNPs) given in the literature were found in both control and patients groups. Moreover one new polymorphism in exon 18 (c.3727G > A) not reported previously was discovered in both groups. It was striking that most of the mutations were found in exons 8, 12-14. This is the first study covering Turkish Wilson disease patients and control groups for mutation screening in all the coding regions of ATP7B gene by DNA sequencing method and adding five new mutations and one polymorphism into the HUGO Wilson disease mutation database.

Successful liver transplantation following veno-arterial extracorporeal membrane oxygenation in a child with fulminant Wilson disease and severe pulmonary hemorrhage: a case report

Massive pulmonary hemorrhage and other serious cardiopulmonary diseases in patients with fulminant hepatitis result not only in graft failure but also mortality after LT. ECMO is used to treat children with cardiorespiratory failure refractory to conventional intensive care. We describe a five-yr-old girl with genetically confirmed fulminant Wilson disease and severe pulmonary hemorrhage who underwent successful primary LT following veno-arterial ECMO. To our knowledge, this is the first report of successful primary LT in a patient using veno-arterial ECMO. The present case demonstrates that ECMO, as a bridging modality to LT, may be necessary to manage both massive pulmonary hemorrhage and possible graft loss because of hypoxemia.

Metals and the liver

PURPOSE OF REVIEW

Hereditary liver diseases resulting in copper and iron overload may cause significant morbidity and mortality if not diagnosed and treated early. The goal of this review is to highlight the key publications on genetics, diagnosis and management of hemochromatosis and Wilson disease over the past 18 months.

RECENT FINDINGS

Several recent advancements have been made in the genetic diagnosis of hemochromatosis and Wilson disease. Uncommon HFE mutations resulting in phenotypic hemochromatosis among C282Y heterozygotes have been identified from HFE gene sequencing. A serum ferritin less than 1000 μg/l in C282Y homozygotes was found to be associated with milder symptoms of hemochromatosis. Deferasirox was shown to reduce iron overload in patients with hemochromatosis and may be an option for patients who cannot tolerate phlebotomy. There was found to be evidence of genotype and phenotype correlation in Wilson disease, which can be diagnosed by genetic sequencing. A modified diagnostic guideline has been developed for children with Wilson disease with mild liver disease that increases the sensitivity and specificity of diagnosis. Also treatment with copper chelating agents has less hepatic treatment failures when compared with zinc monotherapy.

SUMMARY

Advancements in diagnosis of hemochromatosis and Wilson disease may lead to earlier diagnosis and treatment with resulting decrease in morbidity and mortality.

Proteomic analysis of the hepatic tissue of Long-Evans Cinnamon (LEC) rats according to the natural course of Wilson disease

Copper-induced toxicity is important in the pathogenic process of Wilson's disease (WD). Using Long-Evans Cinnamon (LEC) rats, an animal model of WD, the study was undertaken to identify proteins involved in the process of WD and to investigate their functional roles in copper-induced hepatotoxicity. In early stages, expression levels of mitochondrial matrix proteins including agmatinase, isovaleryl coenzyme A dehydrogenase, and cytochrome b5 were downregulated. As mitochondrial injuries progressed, along with subsequent apoptotic processes, expressions of malate dehydrogenase 1, annexin A5, transferrin, S-adenosylhomocysteine hydrolase, and sulfite oxidase 1 were differentially regulated. Notably, the expression of malate dehydrogenase 1 was downregulated while the annexin A5 was overexpressed in an age-dependent manner, indicating that these proteins may be involved in the WD process. In addition, pronounced under-expression of S-adenosylhomocysteine hydrolase in elderly LEC rats, also involved in monoamine neurotransmitter metabolism, indicates that this protein might be related to the development of neurological manifestations in WD. The results of our study help to understand the pathogenic process of WD in hepatic tissues, identifying the important proteins associated with the disease process of WD, and to investigate the molecular pathogenic process underlying the development of neurological manifestations in WD.