Disorders of Copper Metabolism in Children-A Problem too Rarely Recognized.

Copper plays an important role in metabolic processes. Both deficiency and excess of this element have a negative effect and lead to pathological conditions. Copper is a cofactor of many enzymatic reactions. Its concentration depends on the delivery in the diet, the absorption in enterocytes, transport with the participation of ATP7A/ATP7B protein, and proper excretion. Copper homeostasis disorders lead to serious medical conditions such as Menkes disease (MD) and Wilson's disease (WD). A mutation in the ATP7A gene is the cause of Menkes disease, it prevents the supply of copper ions to enzymes dependent on them, such as dopamine ß-hydroxylase and lysyl oxidase. This leads to progressive changes in the central nervous system and disorders of the connective tissue. In turn, Wilson's disease is an inherited autosomal recessive disease. It is caused by a mutation of the ATP7B gene encoding the ATP7B protein which means excess copper cannot be removed from the body, leading to the pathological accumulation of this element in the liver and brain. The clinical picture is dominated by the liver, neurological, and/or psychiatric symptoms. Early inclusion of zinc preparations and chelating drugs significantly improves the prognosis in this group of patients. The aim of the study is to analyse, based on the latest literature, the following factors: the etiopathogenesis, clinical picture, diagnostic tests, treatment, prognosis, and complications of disease entities associated with copper disturbances: Menkes disease and Wilson's disease. In addition, it is necessary for general practitioners, neurologists, and gastroenterologists to pay attention to these disease entities because they are recognized too late and too rarely, especially in the paediatric population.

Deep intronic variant causes aberrant splicing of ATP7A in a family with a variable occipital horn syndrome phenotype.

Genetic variants in ATP7A are associated with a spectrum of X-linked disorders. In descending order of severity, these are Menkes disease, occipital horn syndrome, and X-linked distal spinal muscular atrophy. After 30 years of diagnostic investigation, we identified a deep intronic ATP7A variant in four males from a family affected to variable degrees by a predominantly skeletal phenotype, featuring bowing of long bones, elbow joints with restricted mobility which dislocate frequently, coarse curly hair, chronic diarrhoea, and motor coordination difficulties. Analysis of whole genome sequencing data from the Genomics England 100,000 Genomes Project following clinical re-evaluation identified a deep intronic ATP7A variant, which was predicted by SpliceAI to have a modest splicing effect. Using a mini-gene splicing assay, we determined that the intronic variant results in aberrant splicing. Sanger sequencing of patient cDNA revealed ATP7A transcripts with exon 5 skipping, or inclusion of a novel intron 4 pseudoexon. In both instances, frameshift leading to premature termination are predicted. Quantification of ATP7A mRNA transcripts using a qPCR assay indicated that the majority of transcripts (86.1 %) have non-canonical splicing, with 68.0 % featuring exon 5 skipping, and 18.1 % featuring the novel pseudoexon. We suggest that the variability of the phenotypes within the affected males results from the stochastic effects of splicing. This deep intronic variant, resulting in aberrant ATP7A splicing, expands the understanding of intronic variation on the ATP7A-related disease spectrum.

Response of Fibroblasts from Menkes' and Wilson's Copper Metabolism-Related Disorders to Ionizing Radiation: Influence of the Nucleo-Shuttling of the ATM Protein Kinase.

Menkes' disease (MD) and Wilson's disease (WD) are two major copper (Cu) metabolism-related disorders caused by mutations of the ATP7A and ATP7B ATPase gene, respectively. While Cu is involved in DNA strand breaks signaling and repair, the response of cells from both diseases to ionizing radiation, a common DNA strand breaks inducer, has not been investigated yet. To this aim, three MD and two WD skin fibroblasts lines were irradiated at two Gy X-rays and clonogenic cell survival, micronuclei, anti-γH2AX, -pATM, and -MRE11 immunofluorescence assays were applied to evaluate the DNA double-strand breaks (DSB) recognition and repair. MD and WD cells appeared moderately radiosensitive with a delay in the radiation-induced ATM nucleo-shuttling (RIANS) associated with impairments in the DSB recognition. Such delayed RIANS was notably caused in both MD and WD cells by a highly expressed ATP7B protein that forms complexes with ATM monomers in cytoplasm. Interestingly, a Cu pre-treatment of cells may influence the activity of the MRE11 nuclease and modulate the radiobiological phenotype. Lastly, some high-passage MD cells cultured in routine may transform spontaneously becoming immortalized. Altogether, our findings suggest that exposure to ionizing radiation may impact on clinical features of MD and WD, which requires cautiousness when affected patients are submitted to radiodiagnosis and, eventually, radiotherapy.

The Tao of copper metabolism: from physiology to pathology.

As a transitional metal, copper plays a crucial role in maintaining the normal physiological activities of mammals. The intracellular copper concentration is meticulously regulated to maintain extremely low levels through homeostatic regulation. Excessive accumulation of free copper in cells can have deleterious effects, as observed in conditions such as Wilson's disease. Moreover, data accumulated over the past few decades have revealed a crucial role of copper imbalance in tumorigenesis, progression and metastasis. Recently, cuproptosis, also known as copper-induced cell death, has been proposed as a novel form of cell death. This discovery offers new prospects for treating copper-related diseases and provides a promising avenue for developing copper-responsive therapies, particularly in cancer treatment. We present a comprehensive overview of the Yin-Yang equilibrium in copper metabolism, particularly emphasising its pathophysiological alterations and their relevance to copper-related diseases and malignancies.

Copper-transporting ATPases throughout the animal evolution - From clinics to basal neuron-less animals.

Copper-transporting ATPases are a group of heavy metal-transporting proteins and which can be found in all living organisms. In animals, they are generally referred to as ATP7 proteins and are involved in many different physiological processes including the maintaining of copper homeostasis and the supply of copper to cuproenzymes. A single ATP7 gene is present in non-chordate animals while it is divided into ATP7A and ATP7B in chordates. In humans, dysfunction of ATP7 proteins can lead to severe genetic disorders, such as, Menkes disease and Wilson's disease, which are characterized by abnormal copper transport and accumulation, causing significant health complications. Therefore, there is a substantial amount of research on ATP7 genes and ATP7 proteins in humans and mice to understand pathophysiological conditions and find potential therapeutic interventions. Copper-transporting ATPases have also been investigated in some non-mammalian vertebrates, protostomes, single-cellular eukaryotes, prokaryotes, and archaea to gain useful evolutionary insights. However, ATP7 function in many animals has been somewhat neglected, particularly in non-bilaterians. Previous reviews on this topic only broadly summarized the available information on the function and evolution of ATP7 genes and ATP7 proteins and included only the classic vertebrate and invertebrate models. Given this, and the fact that a considerable amount of new information on this topic has been published in recent years, the present study was undertaken to provide an up-to-date, comprehensive summary of ATP7s/ATP7s and give new insights into their evolutionary relationships. Additionally, this work provides a framework for studying these genes and proteins in non-bilaterians. As early branching animals, they are important to understand the evolution of function of these proteins and their important role in copper homeostasis and neurotransmission.

Menkes disease complicated by concurrent ACY1 deficiency: A case report.

Introduction: Menkes disease is an X-linked recessive condition caused by mutations in the ATP7A gene, which leads to severe copper deficiency. Aminoacylase-1 deficiency is a rare inborn error of metabolism caused by homozygous or compound heterozygous variant in the ACY1 gene, characterized by increased urinary excretion of specific N-acetyl amino acids. Case presentation: We report an infant with neurological findings such as seizures, neurodevelopmental delay and hypotonia. Metabolic screening showed low serum copper and ceruloplasmin, and increased urinary excretion of several N-acetylated amino acids. Whole-exome sequencing analysis (WES) revealed the novel de novo variant c.3642_3649dup (p.Ala1217Aspfs*2) in the ATP7A gene, leading to a diagnosis of Menkes disease, and the simultaneous presence of the homozygous ACY1 variant c.1057C>T (p.Arg353Cys) causative of Aminoacylase-1 deficiency. Conclusion: Our patient had two rare conditions with different treatment courses but overlapping clinical features. The identified novel ATP7A mutation associated with Menkes disease expands the ATP7A gene spectrum.

Ethics in pre-ART genetics: a missed X-linked Menkes disease case.

Assisted reproductive technology (ART) has experienced dramatic progress over the last 30 years, and gamete donation is routine in fertility clinics. Major advances in genetic diagnostics are part of this development due to the ability to analyze multiple genes or whole genomes fast and to an affordable prize. This requires knowledge and capability to evaluate genetic variants correctly in a clinical setting. Here we report a Menkes disease case, born after ART, where genetic screening and variant scoring failed to identify an egg donor as carrier of this fatal X-linked disorder. The gene variant is a deletion of a single base pair leading to a frameshift and premature termination of the protein, predicted to result in no or severely diminished function. The variant would be classified as likely pathogenic (class 4) and should be readily detectable by molecular genetic screening techniques. We wish to highlight this case to prevent future similar cases. IVI Igenomix has developed and embarked on an ambitious screening program to detect and prevent a large number of inherited severe childhood disorders in ART pregnancies. The company has recently achieved ISO 15189 certification with competence to evaluate and deliver timely, accurate, and reliable results. Failure to identify a pathogenic variant in the ATP7A gene leading to birth of two boys with Menkes disease invokes the required procedures to screen and detect disease-causing gene variants. This calls for ethical and legal considerations in ART diagnostics to prevent fatal errors like the present.

Health-Related Quality of Life and Family Functioning of Primary Caregivers of Children with Menkes Disease.

BACKGROUND: Menkes disease (MD; OMIM #309400) is a progressive neurodegeneration that results from abnormalities in the copper metabolism which are already present before birth. It is an extremely rare condition. The study was conducted to assess the quality of life of children with MD syndrome and the impact of the disease on family functioning. METHODS: A cross-sectional questionnaire survey was used. The subjects were 16 parents of children with MD. The method used was the Paediatric Quality of Life Inventory and the PedsQL Family Impact Module and the author's own questionnaire. RESULTS: Quality of life (QOL) was 29.14 (SD = 14.73), with the lowest for physical functioning (M = 10.55; SD = 10.26) and highest for emotional functioning (M = 48.13; SD = 29.43). The highest score was on the family relationships domain (M = 56.25, SD = 20.38) and the cognitive functioning domain (M = 50.00, SD = 19.24) and the lowest was on the daily activities' domain (M = 32.29, SD = 20.38) and the physical functioning domain (M = 39.84, SD = 14.90). The analysis did not show statistically significant relationships between age (p = 0.193) and the number of epileptic seizures a week (p = 0.641) and the overall QOL of the children studied. No statistically significant relationships were found between treatment with copper histidine and the overall QOL of the children (p = 0.914) and in physical functioning (p = 0.927), emotional functioning (p = 0.706), and social functioning (p = 0.751). The presence of comorbidities did not have an influence on the overall QOL. CONCLUSIONS: MD has a moderate impact on the functioning of the families of the affected children. The age of the child, number of epileptic seizures a week, feeding method (oral feeding or feeding via a PEG tube), and treatment with copper histidine do not have a significant impact on the QOL of children with MD.

ATP7A-related copper transport disorders: A systematic review and definition of the clinical subtypes.

In patients with ATP7A-related disorders, counseling is challenging due to clinical overlap between the entities, the absence of predictive biomarkers and a clear genotype-phenotype correlation. We performed a systematic literature review by querying the MEDLINE and Embase databases identifying 143 relevant papers. We recorded data on the phenotype and genotype in 162 individuals with a molecularly confirmed ATP7A-related disorder in order to identify differentiating clinical criteria, evaluate genotype-phenotype correlations and propose management guidelines. Early seizures are specific for classical Menkes disease (CMD), that is characterized by early-onset neurodegenerative disease with high mortality rates. Ataxia is an independent indicator for atypical Menkes disease, that shows better survival rates than CMD. Bony exostoses, radial head dislocations, herniations and dental abnormalities are specific for occipital horn syndrome (OHS) that may further present with developmental delay and connective tissue manifestations. Intracranial tortuosity and bladder diverticula, both with high risk of complications, are common among all subtypes. Low ceruloplasmin is a more sensitive and discriminating biomarker for ATP7A-related disorders than serum copper. Truncating mutations are frequently associated with CMD, in contrast with splice site and intronic mutations which are more prevalent in OHS.

Fatal congenital copper transport defect caused by a homozygous likely pathogenic variant of SLC31A1.

Known hereditary human diseases featuring impaired copper trafficking across cellular membranes involve ATP7A (Menkes disease, occipital horn disease, X-linked spinal muscular atrophy type 3) and ATP7B (Wilson disease). Herein, we report a newborn infant of consanguineous parents with a homozygous pathogenic variant in a highly conserved sequence of SLC31A1, coding for the copper influx transporter 1, CTR1. This missense variant, c.236T > C, was detected by whole exome sequencing. The infant was born with pulmonary hypoplasia and suffered from severe respiratory distress immediately after birth, necessitating aggressive mechanical ventilation. At 2 weeks of age, multifocal brain hemorrhages were diagnosed by cerebral ultrasound and magnetic resonance imaging, together with increased tortuosity of cerebral arteries. Ensuing seizures were only partly controlled by antiepileptic drugs, and the infant became progressively comatose. Laboratory investigations revealed very low serum concentrations of copper and ceruloplasmin. No hair shaft abnormalities were detected by dermatoscopy or light microscopic analyses of embedded hair shafts obtained at 4 weeks of life. The infant died after redirection of care and elective cessation of invasive mechanical ventilation at 1 month of age. This case adds SLC31A1 to the genes implicated in severe hereditary disorders of copper transport in humans.

Mitochondrial copper in human genetic disorders.

Copper is an essential micronutrient that serves as a cofactor for enzymes involved in diverse physiological processes, including mitochondrial energy generation. Copper enters cells through a dedicated copper transporter and is distributed to intracellular cuproenzymes by copper chaperones. Mitochondria are critical copper-utilizing organelles that harbor an essential cuproenzyme cytochrome c oxidase, which powers energy production. Mutations in copper transporters and chaperones that perturb mitochondrial copper homeostasis result in fatal genetic disorders. Recent studies have uncovered the therapeutic potential of elesclomol, a copper ionophore, for the treatment of copper deficiency disorders such as Menkes disease. Here we review the role of copper in mitochondrial energy metabolism in the context of human diseases and highlight the recent developments in copper therapeutics.

Evaluation of hair structural abnormalities in children with different neurological diseases.

BACKGROUND: Hair microscopy is a fast and effortless diagnostic method for many diseases affecting hair in daily practice. Many diseases can present with hair shaft disorders in pediatric neurology practice. METHODS: Children with pathological hair findings were included in our study. Microscopic evaluation of the hair was performed under light microscopy. The clinical findings, pathological hair shaft findings, laboratory tests, and final diagnosis of the patients were evaluated. RESULTS: In our study, 16 patients with rare pathological hair findings were identified. Of these 16 patients, nine were diagnosed with giant axonal neuropathy, three with Griscelli syndrome, two with Menkes disease, and two with autosomal recessive woolly hair disease. In hair inspection, curly and tangled hair in patients with giant axonal neuropathy; silvery blond hair in patients with Griscelli syndrome; sparse, coarse, and light-colored hair in patients with Menkes disease; and hypotrichosis in patients with autosomal recessive woolly hair were remarkable findings. Dystrophic hair was detected in most of the patients on light microscopy. In addition, signs of trichorrhexis nodosa, tricoptylosis, and pili torti were found. In particular, pigment deposition in the hair shaft of two patients diagnosed with Griscelli syndrome and pili torti findings in two patients with Menkes disease were the most important findings suggestingthe diagnosis. CONCLUSIONS: Detection of hair findings in the physical examination and performing light microscopic evaluation facilitates the diagnosis of rare diseases accompanied by hair findings. A hair examination should be performed as a part of physical and neurological examinationson eachpatient regardless of thecomplaint.

Heterogeneous nuclear ribonucleoprotein hnRNPA2/B1 regulates the abundance of the copper-transporter ATP7A in an isoform-dependent manner.

Copper (Cu) is an essential micronutrient with a critical role in mammalian growth and development. Imbalance of Cu causes severe diseases in humans; therefore, cellular Cu levels are tightly regulated. Major Cu-transport proteins and their cellular behavior have been characterized in detail, whereas their regulation at the mRNA level and associated factors are not well-understood. We show that the heterogeneous nuclear ribonucleoprotein hnRNPA2/B1 regulates Cu homeostasis by modulating the abundance of Cu(I)-transporter ATP7A. Downregulation of hnRNPA2/B1 in HeLa cells increases the ATP7A mRNA and protein levels and significantly decreases cellular Cu; this regulation involves the 3' UTR of ATP7A transcript. Downregulation of B1 and B1b isoforms of hnRNPA2/B1 is sufficient to elevate ATP7A, whereas overexpression of either hnRNPA2 or hnRNPB1 isoforms decreases the ATP7A mRNA levels. Concurrent decrease in hnRNPA2/B1, increase in ATP7A, and a decrease in Cu levels was observed in neuroblastoma SH-SY5Y cells during retinoic acid-induced differentiation; this effect was reversed by overexpression of B1/B1b isoforms. We conclude that hnRNPA2/B1 is a new isoform-specific negative regulator of ATP7A abundance.

Decreased Expression of the Slc31a1 Gene and Cytoplasmic Relocalization of Membrane CTR1 Protein in Renal Epithelial Cells: A Potent Protective Mechanism against Copper Nephrotoxicity in a Mouse Model of Menkes Disease.

Kidneys play an especial role in copper redistribution in the organism. The epithelial cells of proximal tubules perform the functions of both copper uptake from the primary urine and release to the blood. These cells are equipped on their apical and basal membrane with copper transporters CTR1 and ATP7A. Mosaic mutant mice displaying a functional dysfunction of ATP7A are an established model of Menkes disease. These mice exhibit systemic copper deficiency despite renal copper overload, enhanced by copper therapy, which is indispensable for their life span extension. The aim of this study was to analyze the expression of Slc31a1 and Slc31a2 genes (encoding CTR1/CTR2 proteins) and the cellular localization of the CTR1 protein in suckling, young and adult mosaic mutants. Our results indicate that in the kidney of both intact and copper-injected 14-day-old mutants showing high renal copper content, CTR1 mRNA level is not up-regulated compared to wild-type mice given a copper injection. The expression of the Slc31a1 gene in 45-day-old mice is even reduced compared with intact wild-type animals. In suckling and young copper-injected mutants, the CTR1 protein is relocalized from the apical membrane to the cytoplasm of epithelial cells of proximal tubules, the process which prevents copper transport from the primary urine and, thus, protects cells against copper toxicity.

Oral Elesclomol Treatment Alleviates Copper Deficiency in Animal Models.

Copper (Cu) is an essential trace element for key biochemical reactions. Dietary or genetic copper deficiencies are associated with anemia, cardiomyopathy, and neurodegeneration. The essential requirement for copper in humans is illustrated by Menkes disease, a fatal neurodegenerative disorder of early childhood caused by mutations in the ATP7A copper transporter. Recent groundbreaking studies have demonstrated that a copper delivery small molecule compound, elesclomol (ES), is able to substantially ameliorate pathology and lethality in a mouse model of Menkes disease when injected as an ES-Cu2+ complex. It is well appreciated that drugs administered through oral means are more convenient with better efficacy than injection methods. Here we show, using genetic models of copper-deficient C. elegans and mice, that dietary ES supplementation fully rescues copper deficiency phenotypes. Worms lacking either the homolog of the CTR1 copper importer or the ATP7 copper exporter showed normal development when fed ES. Oral gavage with ES rescued intestine-specific Ctr1 knockout mice from early postnatal lethality without additional copper supplementation. Our findings reveal that ES facilitates copper delivery from dietary sources independent of the intestinal copper transporter CTR1 and provide insight into oral administration of ES as an optimal therapeutic for Menkes disease and possibly other disorders of copper insufficiency.

Almost misdiagnosed Menkes disease: A case report.

Background: Menkes disease is a disorder of copper metabolism and which follows a progressive degeneration of brain. It is a rare X-linked recessive disorder that results from mutations in ATP7A gene. The early diagnosis of Menkes disease is critical to patients' prognosis. Case presentation: We report a case of Menkes disease. A 4-month-old boy presented with intermittent convulsions for a week. The brain MRI showed excessive tortuosities of intracranial vessels, and radiologists prompted for further examinations to confirm that it was Menkes disease. Patient was advised for biochemical investigations and genetic tests. Reduced level of ceruloplasmin (0.04 g/L; normal range, 0.2-0.6 g/L) was revealed. Genetic testing revealed a missense mutation within exon 18, c.3548 G > A, p.G1183D. This patient was almost misdiagnosed as epilepsy. Fortunately, based on the clues from radiologist, further physical examination and experimental tests were carried out. Conclusion: We reported the imaging features of a case of Menkes disease, which can provide clinicians with more clues to consider the possibility of this rare disease.

Identification of a Novel Deep Intronic Variant by Whole Genome Sequencing Combined With RNA Sequencing in a Chinese Patient With Menkes Disease.

Background: Menkes disease (MD) is a rare X-linked connective tissue disorder of copper metabolism caused by pathogenic variant(s) in ATP7A gene. The aim of the present study is to determine the clinical characteristics and molecular basis of one patient with MD. Methods: One 10-month-old Chinese boy who met the clinical manifestations of MD was enrolled in this study. Whole genome sequencing (WGS) was performed in the patient in order to identify the variant(s), followed by Sanger sequencing. RNA sequencing (RNA-seq) from whole blood was subsequently applied to assess the effect of variant on transcription levels, and reverse transcriptase-polymerase chain reaction (RT-PCR) was performed for further validation. In addition, X chromosome inactivation (XCI) status of the patient's mother at the DNA level was measured by capillary electrophoresis. Results: The patient suffered from intermittent convulsions for more than 6 months, with psychomoto retardation and neurodegenerations. The patient also had curly hair, hypopigmented skin, cutis laxa, decreased muscle strength and hypotonia. MRI showed the intracranial arteries were tortuous with some "spiral" changes. The patient's serum ceruloplasmin level was low. WGS revealed one novel hemizygous variant, c.2627-501C > T (NM_000,052.7), located in the deep intronic sequence of ATP7A gene. Sanger sequencing confirmed that the variant was inherited from his mother. RNA-seq confirmed the variant itself, and identified a pseudo-exon inserted between exons 12 and 13 in mRNA of ATP7A. The sequencing results of RT-PCR from the patient confirmed this finding, while neither of his parents detected aberrant splicing. The Capillary electrophoresis results showed that the patient's mother had a skewed XCI. Conclusion: Our finding of the variant enlarges the variant spectrum in the ATP7A gene. This is a novel deep intronic variant which leads to the activation of a pseudo-exons in the ATP7A gene, and it demonstrates the usefulness of WGS combined with RNA-seq, in terms of revealing disease-causing variants in non-coding regions. Furthermore, the fact that the deep intronic variants cause disease by the activation of pseudo-exon inclusion indicates that in MD this might be an important mechanism.

Early clinical signs and treatment of Menkes disease.

Menkes disease (MD) is an X-linked recessive disorder caused by mutations in ATP7A. Patients with MD exhibit severe neurological and connective tissue disorders due to copper deficiency and typically die before 3 years of age. Early treatment with copper injections during the neonatal period, before the occurrence of neurological symptoms, can alleviate neurological disturbances to some degree. We investigated whether early symptoms can help in the early diagnosis of MD. Abnormal hair growth, prolonged jaundice, and feeding difficulties were observed during the neonatal period in 20 of 69, 16 of 67, and 3 of 18 patients, respectively. Only three patients visited a physician during the neonatal period; MD diagnosis was not made at that point. The mean age at diagnosis was 8.7 months. Seven patients, who were diagnosed in the prenatal stage or soon after birth, as they had a family history of MD, received early treatment. No diagnosis was made based on early symptoms, highlighting the difficulty in diagnosing MD based on symptoms observed during the neonatal period. Patients who received early treatment lived longer than their elderly relatives with MD. Three patients could walk and did not have seizures. Therefore, effective newborn screening for MD should be prioritized.

Usefulness of Trichoscopy over Hair Light Microscopy in Menkes Disease.

Menkes disease (MD) is a rare X-linked recessive neurodegenerative disorder caused by mutations in the ATP7A gene, with a high mortality rate within the first 3 years of life. It typically affects males and is characterized by impaired copper distribution and malfunction of several copper-dependent enzymes. Patients develop progressive muscle hypotonia associated with neurological damage and hair shaft dysplasia - particularly pili torti. Pili torti is usually very subtle in the first 3 months of life and gradually increases during the first year. Light microscopy examination in search for pili torti requires the observation of more than 50 hair shafts. In contrast, trichoscopy with a hand-held dermatoscope allows to easily identify the hair shaft defect. We report a case of a Hispanic male infant with MD in whom we show that trichoscopy is superior to hair light microscopy in revealing pili torti.