ATP7B variant spectrum in a French pediatric Wilson disease cohort

Clinical and Molecular Spectrum of Wilson Disease in the Arab World: A Systematic Review

Wilson disease is a rare monogenic disease characterized by copper overload in various organs, mainly the liver, the brain and the eyes. It has a prevalence ranging between 1/30,000 and 1/50,000, and it is caused by pathogenic variants in the ATP7B gene, which encodes a copper-transporting ATPase essential for regulating liver copper levels by directing copper to the secretory pathway and exporting excess copper into bile. It is a fatal disease if left untreated; however early diagnosis and effective treatment enable patient's outcome improvement. Unfortunately, in the Arab world there is no collective data on Wilson disease. This systematic review presents an explicit overview on the clinical and molecular spectrum of Wilson disease in the Arab world. A literature search was conducted on five databases from their inception until April 2024, using a combination of words related to the genetics of Wilson disease in the Arab world. The search resulted in 48 relevant studies carried out in 13 Arab countries, in which 802 Wilson disease patients were reported, with a high rate of consanguinity, and a slight male predominance. Hepatic presentations were the most frequent features in patients, and a total of 92 variants were identified with a detection rate of 61.2%. Genotype-phenotype correlations were not established for the majority of variants. This review revealed a clinical and molecular heterogeneity of Wilson disease in the Arab world. Efforts from health authorities, clinicians and geneticists are recommended to improve diagnosis, reduce disease incidence and give more insights into the present-day understanding of Wilson disease in the Arab world.

Copper in human health: From COVID 19 to neurodegenerative diseases

Copper (Cu) exists in two oxidation states Cu+I and Cu+II yielding formation of enzymes involved in biological processes. In higher concentrations, by oxidative process and ROS production, Cu is toxic towards plants, humans and animals livers as observed in Wilson disease or sheep scrapie. Fighting according to the Fenton reaction against bacteria and viruses, has been proposed as a mean of combatting nosocomial diseases and complementary to COVID19 vaccination. In humans, Cu is stocked in liver, muscle or bound to brain protein as ß-APP, tau-protein, α-synuclein, ubiquitin or prion which present antioxidant properties when Cu-bonded. In abnormal ß-sheet conformation, they can trigger neurodegenerative diseases such as Alzheimer(AD), Parkinson(PD) and ALS. In these diseases, blood copper increase correlated with brain copper decrease has been described. In AD, abnormal D-serine has been detected in blood and cerebrospinal fluid. D-glutamate and D-alanine blood levels have been found in AD and could also be controlled with Cu and ceruloplasmin in a possible disease screening test. This abnormal D-conformation might result from epimerization of physiologically L-conformation brain peptides into protease-resistant D-enantiomers. This has previously been experimentally demonstrated for Bovine Spongiform Encephalopathy in a free Cu reductive medium with UV-induced free radicals. The Cu brain protective effect against free radicals was restored with cupric addition in oxidizing medium. Cupric supplementation in the brain, might restore Cu protection and slow down neurodegenerative processes. To lower side effects, Cu amino-acid complexes able to cross the blood brain barrier might be suggested for a Cu transfer to the brain.

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.

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

Background

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.

Objectives

The meta-analysis was performed to comprehensive gain a thorough grasp of the spectrum of genetic variations.

Design

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.

Data sources and methods

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.

Results

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).

Conclusion

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.

Epidemiology of Wilson's Disease and Pathogenic Variants of the ATP7B Gene Leading to Diversified Protein Disfunctions

Wilson's disease (WD) is an autosomal recessive disorder characterized by toxic accumulation of copper in the liver, brain, and other organs. The disease is caused by pathogenic variants in the ATP7B gene, which encodes a P-type copper transport ATPase. Diagnosing WD is associated with numerous difficulties due to the wide range of clinical manifestations and its unknown dependence on the physiological characteristics of the patient. This leads to a delay in the start of therapy and the subsequent deterioration of the patient's condition. However, in recent years, molecular genetic testing of patients using next generation sequencing (NGS) has been gaining popularity. This immediately affected the detection speed of WD. If, previously, the frequency of this disease was estimated at 1:35,000-45,000 people, now, when conducting large molecular genetic studies, the frequency is calculated as 1:7026 people. This certainly points to the problem of identifying WD patients. This review provides an update on the performance of epidemiological studies of WD and describes normal physiological functions of the protein and diversified disfunctions depending on pathogenic variants of the ATP7B gene. Future prospects in the development of WD genetic diagnostics are also discussed.

Wilson Disease and Alpha1-Antitrypsin Deficiency: A Review of Non-Invasive Diagnostic Tests

Wilson disease and alpha1-antitrypsin deficiency are two rare genetic diseases that may impact predominantly the liver and/or the brain, and the liver and/or the lung, respectively. The early diagnosis of these diseases is important in order to initiate a specific treatment, when available, ideally before irreversible organ damage, but also to initiate family screening. This review focuses on the non-invasive diagnostic tests available for clinicians in both diseases. These tests are crucial at diagnosis to reduce the potential diagnostic delay and assess organ involvement. They also play a pivotal role during follow-up to monitor disease progression and evaluate treatment efficacy of current or emerging therapies.

Clinical and Genetic Analysis in Neurological Wilson’s Disease Patients With Neurological Worsening Following Chelator Therapy

Objectives: None of the previous studies have focused on the genetic effect on neurological worsening in neurological Wilson’s disease (WD) patients following chelator therapy. We aimed to evaluate the clinical and genetic role in the occurrence of neurological worsening.

Methods: We retrospectively reviewed the medical records of neurological WD patients who received initial chelator therapy and genetic test. Clinical, laboratory, and genetic data were collected. The genotype was classified into two types: 1) severe mutation genotype: patients who carried at least one of the following three types of mutations: frameshift mutation, splicing mutation, or nonsense mutation; 2) non-severe mutation genotype: patients who only carried missense mutations. Then, the clinical features and genotype of the patients with and without neurological worsening were investigated.

Results: Forty-seven neurological WD patients were identified with a median age at onset of 16.17 years (range 7.75–47 years) and 35 (74.5%) males. The mean interval from onset to diagnosis was 0.6 years (range: 0.5 months-6.25 years). Neurological deterioration was observed in 29 patients (61.7%) and the other 18 patients (38.3%) were stable or improved during anti-copper treatment. The neurological worsening was completely irreversible in 6 cases (20.7%) and partially irreversible in 16 cases (55.2%). The common deteriorated symptoms were as follows: rigidity in 20 cases (69%), speech difficulties in 20 cases (69%)), walking difficulties in 13 cases (44.8%), dysphagia in 9 cases (31%), and salivation in 9 cases (31%). The patients with neurological worsening had significantly younger age (p = 0.028), shorter delayed diagnosis time (p = 0.011), higher rate of dystonia (p = 0.003), and severe mutation genotype (p = 0.036), compared to those without neurological worsening.

Conclusion: We found that younger age of onset, the presence of dystonia, and genotype with severe mutations may be predictive of neurological worsening in the neurological WD patients that received chelator therapy. For those patients, chelator therapy should be given with caution and needs closer observation during follow-up.