Early treatment of Menkes disease with parenteral Cooper-Histidine: Long-term follow-up of four treated patients

Effect of copper and diethyldithiocarbamate combination therapy on the macular mouse, an animal model of Menkes disease

Menkes disease (MD) is a neurodegenerative disorder characterized by a copper deficiency in the brain. It is caused by the defective intestinal absorption of copper resulting from a deficiency of a copper-transporting ATPase, ATP7A. This gives rise to an accumulation of copper in the intestine. The copper deficiency in the brain of MD patients cannot be improved by copper injections, because the administered copper accumulates at the blood-brain barrier and is not transported across to the neurons. To resolve this problem, we investigated the effect of a combination therapy of copper and sodium diethyldithiocarbamate (DEDTC), a lypophilic chelator, in an animal model of MD, the macular mouse. Four-week-old macular mice treated with 50 mug of CuCl2 on the 7th day after birth were used. Experimental mice were given a subcutaneous injection of CuCl2 (4 microg) and an intraperitoneal injection of DEDTC (0.2 mg/g body weight) twice a week for 4 weeks and then sacrificed. Copper concentrations and cytochrome-c oxidase activity in the brains of treated mice were higher than those of control macular mice, which received only copper or saline. The ratios of brain noradrenaline to dopamine and of adrenaline to dopamine were also increased by the treatment, suggesting that the activity of dopamine beta-hydroxylase, a copper-dependent enzyme, was improved by the treatment. Liver and renal function tests showed no abnormalities in the treated mice, although copper concentrations in the kidneys of treated mice were higher than those of control macular mice. These results suggest that DEDTC facilitates the passage of copper across the blood-brain barrier and that the combination therapy of copper and DEDTC may be an effective treatment for the neurological disturbances suffered by patients with MD.

Variable clinical expression of an identical mutation in the ATP7A gene for Menkes disease/occipital horn syndrome in three affected males in a single family

Two maternal half-brothers presented with huge cephalic hematoma, fatal in one. Skin morphology disclosed lack of elastic fibres. Their maternal uncle is moderately mentally handicapped and has extensive connective tissue disorders. In all these patients, an identical missense mutation in the ATP7A gene was found and confirmed Menkes' disease.

X-ray Structure of Physiological Copper(II)−Bis(l-histidinato) Complex

The isolation and the X-ray crystal structure of physiological copper(II)-L-histidine complex are reported. The neutral five-coordinate complex shows distorted square pyramidal geometry with bidentate and tridentate L-histidine ligands. The basic character of the pendent imidazole group and H-bonding interactions of bidentate L-histidine ligand are important for copper transport. The unique structural features help explain the origin of its thermodynamic stability and kinetic reactivity in human blood along with the ternary copper(II)-amino acid complexes. The role of L-histidine in interaction with copper(II)-albumin, in cellular uptake of copper, and in treatment of Menkes disease can be studied using these results.

New approaches to the treatment of mitochondrial disorders

Mitochondrial disorders are among the most common inherited metabolic diseases and the issue of treatment arises on a regular basis. There is no established treatment for mitochondrial disorders and current management is largely supportive, but recent advances in our understanding of the pathophysiology provide hope for novel treatments. Patients with mitochondrial myopathy due to mutations of mitochondrial DNA (mtDNA) may benefit from treatments that move normal mitochondrial genomes from the muscle satellite cells into skeletal muscle, but there are concerns about the long-term effects of this approach. A greater understanding of the pathophysiology of a number of nuclear genetic mitochondrial disorders suggests new avenues for treatment (such as copper-histidine in children with SCO2 gene mutations, and strategies modifying intra-mitochondrial nucleoside pools in the various disorders of mtDNA maintenance). A number of different strategies are also being explored at the molecular level, including the use of antigenomic molecules to mutated mtDNA and the allotropic expression of mutated mtDNA genes within the cell nucleus. Nuclear transfer techniques also provide hope for women at risk of transmitting pathogenic mtDNA mutations.

Reversion of hypertrophic cardiomyopathy in a patient with deficiency of the mitochondrial copper binding protein Sco2: is there a potential effect of copper?

Mutations in Sco2, a protein involved in copper trafficking to the terminal enzyme of the respiratory chain, cytochrome c oxidase, results in infantile hypertrophic cardioencephalomyopathy. We have recently shown that copper-histidine (Cu-his) supplementation of Sco2-deficient myoblasts rescues COX activity in vitro. Here, we report a patient with SCO 2 mutations and with resolution of severe hypertrophic cardiomyopathy. Weighing up the evidence, the most likely explanation for the improved cardiac function in this patient was the subcutaneous application of Cu-his.

The Crystal Structure of a Novel Copper(II) Complex with Asymmetric Ligand Derived from l-Histidine

The crystal structure of a novel copper(II) complex with a potentially hexadentate Schiff base ligand derived from l-histidine has been solved by a single-crystal X-ray diffraction method at pH 7.4. The copper(II) ion is coordinated asymmetrically by a tetradentate ligand with the amino and imidazole imido nitrogen atoms on one side versus imino nitrogen and carboxylate oxygen atoms on the other side in a distorted square-planar geometry. The formation of an infinite chain through carboxylate coordination is observed. The novel ligand is obtained by the reaction between the l-histidine molecules coordinated to copper(II) and 4-hydroxy-4-methylpentan-2-one formed by aldol condensation of acetone. This complex provides insights into a possible structural arrangement between copper(II) and l-histidine which is physiologically important and abundantly present in biological systems.

Biochemical indicator for evaluation of connective tissue abnormalities in Menkes' disease

Metabolites of collagen metabolism were analyzed in patients with Menkes' disease. The urinary deoxypyridinoline level was significantly low in the patients with Menkes' disease, indicating that it is a good marker of lysyl oxidase activity, which is related to the connective tissue abnormalities.

Pamidronate treatment improves bone mineral density in children with Menkes disease

Menkes disease is a severe multisystem disorder due to defective bioavailability and transport of copper at the cellular level. Deficient activity of lysyl oxidase, a copper-dependent enzyme, causes defective collagen cross-linking leading to osteoporosis and pathological fractures in these children. The objective of the study was to evaluate the changes in bone mineral density following pamidronate treatment in children with Menkes disease. The study design was an open observational study of three children with Menkes disease and significant osteoporosis with or without pathological fractures, all of whom received pamidronate treatment for 1 year. There were 34-55% and 16-36% increases in lumbar spine bone mineral content and areal bone mineral density, respectively, following 1 year of treatment with pamidronate. There were no further fractures in two of the three children treated. No adverse effects of pamidronate treatment were noted. Pamidronate treatment was associated with an increase in bone mineral density and may be an effective treatment modality for the management of osteoporosis in children with Menkes disease.

The molecular basis of copper homeostasis copper-related disorders

Copper is an essential trace element that can be extremely toxic in excess due to the pro-oxidant activity of copper ions. Inherited disorders of copper transport, Menkes disease (copper deficiency), and Wilson disease (copper toxicosis) are caused by mutations of two closely related Cu transporting-ATPases, and demonstrate the essentiality and potential toxicity of copper. Other copper toxicosis conditions in humans and animals have been described, but are not well understood at a molecular level. Copper homeostatic mechanisms are being discovered. One such mechanism is copper-induced trafficking of the Cu-ATPases, which allows cells to provide copper to secreted cupro-proteins but also to efflux excess copper. Oxidative damage induced by copper may be involved in the pathogenesis of neurodegenerative conditions such as Alzheimer's disease, familial amyotrophic lateral sclerosis, and prion diseases.

Drug targets in Menkes disease - prospective developments

Menkes disease (MNK) is an X-linked recessive disorder characterised by a copper-transporting ATPase defect. In the affected cells, copper transport from the cytosol to the Golgi apparatus is disturbed, resulting in a reduction of copper efflux. Orally-administered copper, which accumulates in the intestine, cannot be absorbed and thus a copper deficiency arises. The characteristic features of MNK are progressive neurological degeneration, connective tissue disorders and hair abnormalities, which are caused by a reduction in the activity of several copper-dependent enzymes, due to concomitant copper deficiency. Subcutaneous injections of copper-histidine complex, which currently forms the accepted mode of treatment, prevent the neurological degeneration in some patients when the treatment is initiated soon after birth. However, when the treatment is started later, the neurological degenerative processes are not prevented. Moreover, the treatment does not improve the connective tissue disorders that are caused by the low activity of lysyl oxidase. In order to solve these problems, a form of the treatment aimed at delivering copper into the Golgi apparatus should be studied. An attempt is made in this review to present what is currently known about MNK and its variants, the efficacy and problems of currently accepted treatments and finally therapeutic targets in MNK.

Intragenic deletions at Atp7a in mouse models for Menkes disease

Mottled mice have mutations in the copper-transporting ATPase Atp7a. They are proven models for the human disorder Menkes disease (MD), which results from mutations in a homologous gene. Mottled mice can be divided into three classes: class 1, in which affected males die before birth; class 2, in which affected males die in the early postnatal period; and class 3, in which affected males survive to adulthood. In humans, it has been shown that mutations that lead to a complete absence of functional protein cause classical MD, which is characterized by death of boys in early childhood. We hypothesized that the most severely affected mottled alleles would be the most likely to carry mutations equivalent to those causing classical MD and therefore undertook mutational analysis of several class 1 mottled alleles to assess whether these were appropriate models for the disease at the molecular level. Two novel mutations, a deletion of exons 11-14 in mottled spot and an insertion in exon 10 leading to missplicing in mottled candy, were identified. However, these are both "in-frame" mutations, as are the other eight Atp7a mutations reported to date, and therefore no frameshift or nonsense mutations have yet been associated with the mottled phenotype. This contrasts with the mutation spectrum associated with MD, emphasizing the need for caution when mottled mice are used as models for the clinical disorder.

Menkes disease after copper histidine replacement therapy: case report

Menkes disease (MD) is an X-linked recessive disorder of copper metabolism, characterized in its untreated state by progressive disorders of multiple systems, especially the central nervous system (CNS) and connective tissue, and death by 3 years of age. Recently, therapy with copper-histidine has modified the severity of MD and permitted survival into adolescence. Clinical response has been greater for the neurological abnormalities than for the connective tissue abnormalities. In this report, we describe the postmortem pathology of one individual who had received copper-histidine therapy and died at age 10; we believe this to be the first such pathological report. The postmortem examination demonstrated significant pathology of mesenchymal tissues, including skeletal abnormalities, vascular degeneration, and bladder diverticula. The CNS, by contrast, showed minimal pathology. The phenotype was more consistent with occipital horn syndrome, a milder allelic disorder of copper metabolism, than with classic MD. The differential sensitivity of CNS and mesenchymal tissues to copper-histidine therapy may result from heterogeneity in the response of different copper-dependent enzymes.

Menkes disease: case report of an uncommon presentation with white matter lesions

Menkes disease is a rare X-linked disorder related to a defect in the copper metabolism. According to the current literature, the most frequent neuroimaging findings are cortical atrophy, chronic subdural effusion or hygroma, and vascular abnormalities. White matter lesions may be present before other features of the disease and may evolve into atrophy. We hereby report a case of Menkes disease with typical history and progression, and an early phase imaging study with important white matter abnormalities, which could have lead to diagnostic difficulties.

Splenic artery aneurysm in the 1990s

Splenic artery aneurysms (SAA), although rare, are the most common visceral artery aneurysms and are known for their potential for rupture. Pregnancy and portal hypertension have been known as major risk factors. With improved methods of diagnosis and minimally invasive therapy, management and outcome of SAA may change significantly. The purpose of this study was to analyze our institutional experience with SAA during the past decade. Charts of all patients (six women, three men; mean age, 60.5 [range: 31 to 81] years) with diagnoses of SAA from 1988 to 1999 were reviewed. Associated conditions included essential hypertension (6), portal hypertension (3), diabetes (1), intracranial aneurysm (1), and polyarteritis nodosa (1). Six patients were asymptomatic, and three had ruptured SAA. Diagnosis was made by angiography (2), computed tomography (3), ultrasonography (3), and exploratory laparotomy (1). Six patients underwent surgery (five required splenectomy), one had embolization, and two had no intervention. Three postoperative deaths occurred-two (intracranial aneurysm, myocardial infarction) in the first month, one (sepsis) in the ninth month. An association of liver disease with SAA was confirmed; however, no association with pregnancy was noted. Surgical treatment followed traditional methods, and mortality correlated with presence of severe comorbidity.

Defective copper-induced trafficking and localization of the Menkes protein in patients with mild and copper-treated classical Menkes disease

Menkes disease is an X-linked disorder of copper metabolism. An overall copper deficiency reduces the activity of copper-dependent enzymes accounting for the clinical presentation of affected individuals. The Menkes gene product (MNK) is a P-type ATPase and is considered to be the main copper efflux protein in most cells. The protein is located primarily at the trans -Golgi network (TGN), but relocalizes to the plasma membrane in elevated copper conditions to expel the excess copper from the cell. Here we report the first missense mutation which causes mild Menkes disease, a mutation in a successfully copper-treated classical Menkes patient and the effect of each mutation on the localization of MNK within the cell. Using western blot analysis, MNK was detectable in cells from both patients, but appeared to be mislocalized in the treated case. In the mild Menkes patient, the protein appeared to be located in the TGN but failed to redistribute towards the cell periphery in response to copper. This is the first description of a mutation in a Menkes patient which affects the trafficking of MNK, and the loss of this process is consistent with the clinical phenotype.

Menkes disease: study of the mitochondrial respiratory chain in three cases

Mitochondrial oxidative metabolism in three patients with typical Menkes disease was studied. In two cases, a general decrease in all of the respiratory chain complex activities (I, II, III and IV) was observed. However, in the most severe case, these activities were entirely normal. Our results emphasize the diversity of the cellular expression of Menkes disease which can, in some cases, be associated with a mitochondrial encephalomyopathy.

Functional expression of the Wilson disease protein reveals mislocalization and impaired copper-dependent trafficking of the common H1069Q mutation

Wilson disease is an autosomal recessive disorder of hepatic copper metabolism caused by mutations in a gene encoding a copper-transporting P-type ATPase. To elucidate the function of the Wilson protein, wild-type and mutant Wilson cDNAs were expressed in a Menkes copper transporter-deficient mottled fibroblast cell line defective in copper export. Expression of the wild-type cDNA demonstrated trans-Golgi network localization and copper-dependent trafficking of the Wilson protein identical to previous observations for the endogenously expressed protein in hepatocytes. Furthermore, expression of the Wilson cDNA rescued the mottled phenotype as evidenced by a reduction in copper accumulation and restoration of cell viability. In contrast, expression of an H1069Q mutant Wilson cDNA did not rescue the mottled phenotype, and immunofluorescence studies showed that this mutant Wilson protein was localized in the endoplasmic reticulum. Consistent with these findings, pulse-chase analysis demonstrated a 5-fold decrease in the half-life of the H1069Q mutant as compared with the wild-type protein. Maintenance of these transfected cell lines at 28 degreesC resulted in localization of the H1069Q protein in the trans-Golgi network, suggesting that a temperature-sensitive defect in protein folding followed by degradation constitutes the molecular basis of Wilson disease in patients harboring the H1069Q mutation. Taken together, these studies describe a tractable expression system for elucidating the function and localization of the copper-transporting ATPases in mammalian cells and provide compelling evidence that the Wilson protein can functionally substitute for the Menkes protein, supporting the concept that these proteins use common biochemical mechanisms to effect cellular copper homeostasis.