Menkes' disease and swayback. A comparative study of two copper deficiency syndromes

Can Patients with Wilson's Disease Develop Copper Deficiency?

Background

Wilson's disease (WD) is a rare genetic condition characterized by a copper overload in organs secondary to mutation in ATP7B gene. Lifelong decoppering treatments are the keystone of the treatment but must be regularly adapted to obtain a correct copper balance and could lead to copper deficiency (CD).

Objectives

Study the characteristics of CD in WD patients.

Methods

CD cases from our cohort of 338 WD patients have been investigated. CD was defined by the association of serum copper, exchangeable copper and urinary copper excretion assays less than two standard deviations from the mean with cytopenia and/or neurological damage of spinal cord origin. A systematic review of literature about cases of CD in WD patient was performed in PubMed database according to PRISMA guidelines.

Results

Three WD patients were diagnosed with CD in our cohort. Review of the literature found 17 other patients. Most of the patients had anemia and neutropenia associated with neurological symptoms (especially progressive posterior cord syndrome). All the patients were treated with Zinc salts and the symptoms occurred more than a decade after the initiation of treatment. The adaptation of the treatment allowed a correction of the cytopenia but only a partial improvement of the neurological symptoms.

Conclusions

WD patients can develop CD after many years of zinc therapy. Anemia and neutropenia are red flags that should evoke CD.

Modelling Neurological Diseases in Large Animals: Criteria for Model Selection and Clinical Assessment

Issue: The impact of neurological disorders is recognised globally, with one in six people affected in their lifetime and few treatments to slow or halt disease progression. This is due in part to the increasing ageing population, and is confounded by the high failure rate of translation from rodent-derived therapeutics to clinically effective human neurological interventions. Improved translation is demonstrated using higher order mammals with more complex/comparable neuroanatomy. These animals effectually span this translational disparity and increase confidence in factors including routes of administration/dosing and ability to scale, such that potential therapeutics will have successful outcomes when moving to patients. Coupled with advancements in genetic engineering to produce genetically tailored models, livestock are increasingly being used to bridge this translational gap. Approach: In order to aid in standardising characterisation of such models, we provide comprehensive neurological assessment protocols designed to inform on neuroanatomical dysfunction and/or lesion(s) for large animal species. We also describe the applicability of these exams in different large animals to help provide a better understanding of the practicalities of cross species neurological disease modelling. Recommendation: We would encourage the use of these assessments as a reference framework to help standardise neurological clinical scoring of large animal models.

Neurological presentations revealing acquired copper deficiency: diagnosis features, aetiologies and evolution in seven patients

BACKGROUND

Acquired copper deficiency (ACD) is a rare condition usually diagnosed from haematological changes.

AIMS

To characterise the diagnosis features and the evolution of patients with ACD revealed by neurological symptoms.

METHODS

Clinical, biological and magnetic resonance imaging (MRI) data were prospectively analysed at diagnosis and during follow up under copper supplementation.

RESULTS

Seven patients were studied over a 5-year period. Time to diagnosis ranged from 2.5 to 15 months. Subacute ascending paraesthesias and gait disorder were the first symptoms. All patients had a posterior cord syndrome (PCS) with sensory ataxic gait associated with superficial hypoesthesia of the feet; 50% had also lateral cord signs. Electrodiagnostic tests diagnosed a lower limb sensory neuropathy in four patients. Spinal cord MRI was normal in three of seven patients. Anaemia and lymphopenia were diagnosed in six of seven patients. Serum copper was always low, and urinary copper was low or normal. Serum and urinary zinc were high in four patients. Decreased copper intake (stoma/parenteral nutrition, malnutrition, malabsorption with lack of vitamin supplementation after bariatric or other digestive surgeries) was found in four patients, and the chronic use of denture adhesive paste containing zinc was discovered in four patients. One patient had both the causes recorded. After copper supplementation, copper balance and then haematological disturbances were the first features to normalise gradually in 2 months. Radiological myelitis disappeared in 10 months, whereas neurological symptoms improved in six of seven patients after a mean follow up of 2 years.

CONCLUSIONS

Progressive PCS with anaemia and lymphopenia must raise the possibility of an ACD. Early copper supplementation could increase the neurological prognosis.

[Peripheral neuropathy, myelopathy, cerebellar ataxia, and subclinical optic neuropathy associated with copper deficiency occurring 23 years after total gastrectomy]

We report a 61-year-old man with slowly progressive gait disturbance and paresthesia in the lower extremities following a total gastrectomy for gastric cancer 23 years previously. The patient presented with hyperreflexia, peripheral sensory neuropathy, and cerebellar ataxia. Magnetic resonance imaging showed atrophy of the cerebellum, and electrophysiological findings suggested the presence of disorder in both sides of the pyramidal tract, dorsal column, peripheral nerves, and optic nerve. Laboratory findings revealed anemia, neutropenia, and a remarkably low serum copper level (10 microg/dl; normal: 68-128). His serum vitamin E was slightly low and his serum vitamin B12 was within the normal limits. After administering an oral copper supplement, his symptoms improved with normalization of the serum copper level. We need to pay attention to myeloneuropathy caused by copper deficiency if the patient has a past history of total gastrectomy.

Essentiality and toxicity in copper health risk assessment: overview, update and regulatory considerations

Copper (Cu), an essential element required as a cofactor and/or structural component of numerous metalloenzymes, is uniquely positioned as a case study for issues associated with the essential metals health risk assessment, because of its extensive database. Essential elements pose distinct challenges when establishing regulatory guidelines because too little as well as too much intake can produce adverse health consequences and the dose-response curve is roughly U-shaped. Thus, conventional health risk assessment paradigms do not apply to essential elements; the dose-response assessment needs to define an acceptable range of oral intake (AROI) which prevents deficiency by meeting nutritional requirements while avoiding toxicity due to high intakes. The conceptual framework for this type of risk assessment includes consideration of biological processes that are unique to essential elements-homeostasis, basal and normative nutritional requirements, bioavailability, and nutrient-nutrient interactions. In this paper, the Cu database on physiology, deficiency, and excess is briefly reviewed in order to establish the range of potential health hazards associated with varying levels of intake. Issues discussed include the (1) development of suitable dose-response methodologies, including appropriate dose and response metrics, for Cu; (2) categorization of severity of response and functional significance; (3) use of endpoints of similar severity and functionality for deficiency and excess in dose-response assessment; (4) development of valid biomarkers for subclinical effects, exposures and susceptibilities. Guideline values for Cu intake have been established by nutritional and toxicologic regulatory or advisory boards. Although regulators are more concerned with the potential human toxicity arising from excessive Cu intake, the preponderance of evidence suggests that deficiency is more of a public health concern than excess.

Subacute combined degeneration due to copper deficiency

There is growing clinical evidence supporting a connection between copper deficiency and subacute combined degeneration. While nearly half of patients with copper deficiency myelopathy exhibit MRI abnormalities, signal changes are often ill-defined in distribution. We report a patient with sensory ataxia and spastic paraplegia from copper deficiency whose MRI demonstrates abnormal signal restricted to the dorsal and lateral columns, providing clear radiological support of an association between hypocupremia and combined system degeneration.

Nutritional neuropathies

Optimal functioning of the central and peripheral nervous system is dependent on appropriate nutrients. Neurologic consequences of nutritional deficiencies are not restricted to underdeveloped countries. Multiple nutritional deficiencies can coexist. Obesity is of particular concern in the developed world. The rising rate of bariatric surgery are accompanied by neurologic complications related to nutrient deficiencies. Prognosis depends on prompt recognition and institution of appropriate therapy. This review discusses peripheral nervous system manifestations related to the deficiency of key nutrients, neurologic complications associated with bariatric surgery, and conditions that have a geographic significance associated with bariatric surgery and certain conditions that have a geographic predilection.

Motor neuron disease associated with copper deficiency

Copper deficiency in humans is a rare cause of myeloneuropathy that usually presents with a spastic ataxic gait, hyperreflexia, and distal sensory loss similar to that seen in patients with subacute combined degeneration. We describe three copper-deficient patients, two of whom were referred with a presumptive diagnosis of amyotrophic lateral sclerosis, who had progressive asymmetric weakness or electrodiagnostic findings of proximal and distal denervation suggestive of lower motor neuron disease. Copper replacement resulted in stabilization or mild improvement in weakness. The clinical spectrum of human copper deficiency should include lower motor neuron disease in addition to a syndrome of spastic ataxia.

Copper deficiency myelopathy (human swayback)

The hematologic manifestations of copper deficiency are well known and include anemia and neutropenia. In the past few years, the neurological manifestations of acquired copper deficiency in humans has been recognized, the most common being a myelopathy presenting with a spastic gait and prominent sensory ataxia. The known causes of acquired copper deficiency include prior gastric surgery, excessive zinc ingestion, and malabsorption; however, often the cause is unclear. Hyperzincemia may be present even in the absence of exogenous zinc ingestion. The clinical features and neuroimaging findings are similar to the subacute combined degeneration seen in patients with vitamin B12 deficiency. Copper and vitamin B12 deficiency may coexist. The neurological syndrome may be present without the hematologic manifestations. Copper supplementation resolves the anemia and neutropenia promptly and completely and may prevent the neurological deterioration. Improvement, when it occurs, is often subjective and preferentially involves sensory symptoms. This article describes patients with copper deficiency myelopathy seen at the Mayo Clinic in Rochester, Minn, and reviews the literature on neurological manifestations of acquired copper deficiency in humans.

Imaging features of copper deficiency myelopathy: a study of 25 cases

Acquired copper deficiency presents with a spastic gait and sensory ataxia. Spinal cord magnetic resonance imaging (MRI) in patients with copper deficiency myelopathy may show increased T2 signal, most commonly in the dorsal midline cervical and thoracic cord. These imaging findings may be reversible with normalization of serum copper. The clinical and imaging picture is very similar to the subacute combined degeneration seen in patients with vitamin B12 deficiency. Neuroradiologists should consider this possibility when a long segment of symmetric dorsal spinal cord T2-hyperintensity is identified.

Sheep have an unusual variant of the brain-specific metallothionein, metallothionein-III

Sheep metallothionein-III (MT-III) cDNA was isolated from a brain cDNA library and characterized. In contrast with MT-III from other species, sheep MT-III cDNA is predicted to encode a protein with significantly different metal-binding properties, owing to the loss of three of its cysteine residues. RT-PCR from other sheep confirmed that this aberrant structure is ubiquitous in this species. MT-III was successfully isolated from sheep brain, demonstrating that the cDNA does give rise to a protein product of the predicted structure. Sheep MT-III is similar to other mammalian MT-IIIs in that it retains the Cys-Pro-Cys-Pro motif which is thought to encode growth-inhibitory activity, and we show that it is likewise able to inhibit neuron survival in vitro. This is the first naturally occurring variant of MT-III (or any other major mammalian MT gene) which gives rise to a protein product. These findings are discussed in light of proposed roles of MT in the mammalian brain.

Cerebellar basket cells of Creutzfeldt-Jakob disease: immunohistochemical and ultrastructural study

To elucidate possible abnormalities of cerebellar basket cells of Creutzfeldt-Jakob disease (CJD), seven sporadic cases were examined neuropathologically. Recently, parvalbumin-positive, GABAergic cerebral interneurons have been demonstrated to show early, selective loss in CJD, and the phenomenon is postulated as a cause of characteristic neurological symptoms of CJD. In this study, however, we demonstrated that the basket cells, cerebellar counterparts, were resistant even in patients with severe brain atrophy, and their processes showed intense argyrophilia and immunopositivity to phosphorylated neurofilament. They can newly be listed as CJD-resistant neurons similar to those of the hippocampus and brainstem nuclei. The mechanism to escape cell loss is of great interest, and there might be unknown factors modulating susceptibility within parvalbumin-positive neuronal subgroups. Furthermore, one case showed abnormal positivity with hematoxylin, crystal violet and pyronin in the basket cells. The pyronin positivity was reduced after ribonuclease digestion, suggesting that the causative substance was composed of RNA. Ultrastructurally, the fibers contained free ribosomes and amorphous electron-dense deposits. To our knowledge, such a finding has also not been previously reported.

Cytochrome-c oxidase isolated from the brain of swayback-diseased sheep displays unusual structure and uncharacteristic kinetics

Swayback disease, a neurodegenerative disorder of lambs, and Menkes disease, the human equivalent, are caused by a deficiency of dietary copper. Reports of low enzymic activity suggest that several copper-containing enzymes, including cytochrome-c oxidase (COX), may influence the progress of these diseases. To investigate its role in the development of neurodegenerative disorders, in particular swayback disease, we isolated COX from the brains and livers of swayback-diseased lambs. Comparative sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) combined with densitometric analysis revealed that whereas the structure of COX from the liver of diseased animals was normal, the corresponding brain enzyme was subunits II-, III-, and IV-deficient; the deficiency was 55, 30, and 65% respectively. The activities of liver and brain COX from normal and diseased lambs were compared by polarographic assay at low ionic strength. Whereas the enzyme from normal brains and both forms of the liver enzyme yielded characteristic biphasic Eadie-Hofstee plots, the brain enzyme from diseased animals displayed a single phase with a K(m) of 4.7 +/- 2.4 x 10(-6) M: the K(m) values of COX from the normal brain were 12 +/- 2.5 x 10(-6) and 5.5 +/- 0.5 x 10(-7) M. We conclude that the altered enzyme structure accounts for the uncharacteristic kinetics and low activity we have observed for the isolated brain enzyme. We also conclude that the altered enzyme structure partly accounts for the low oxidase activity and decreased ATP synthesis that has been widely reported for brain tissue from swayback-diseased animals. We postulate that the subunit deficiency probably results from incomplete crosslinking between the subunits and the membrane, and predict that similar structural and kinetic factors may also account for low COX activity in Menkes disease.

Menkes' kinky hair disease: morphological and immunohistochemical comparison of two autopsied patients

An autopsied patient with Menkes' kinky hair disease, who showed unusually long survival until the age of five years with typical neuropathological changes, was examined for distribution of neuronal depletion in the cerebral cortex, and the cerebellar changes were compared morphologically and immunohistochemically with those found in a younger patient (1 year 8 months old) reported previously. Neuronal loss in the cerebral cortex in the both cases, which was ill-defined and unassociated with gliosis, was preferentially distributed in the fifth and sixth layers, especially of the gyral bottom in almost all lobes in the older case. Therefore, this change was thought to be secondary to local ischemia caused by mechanical distortion at the stage of gyrus formation in addition to abnormal development. Ultrastructurally, a prominent increase of confronting cisternae (CC) complexes was found in the perikaryon and processes of Purkinje cells in both cases, and in the older patient CC complexes were arranged more densely and were transformed into concentric lamellar structures in the swollen dendrites. Immunohistochemically, the stainability of neurofilaments (NF, 200 kDa) in Purkinje cells, with or without somatic sprouts was faint or negative in the older patient compared with the marked or moderate positivity in the younger patient and age-matched controls. Empty baskets were absent and NF-positive axonal terminals and synaptophysin-positive granules on Purkinje cells were markedly decreased in both cases. These changes suggest that Purkinje cells degenerate progressively with time and that basket cells also are simultaneously involved.

Golgi study on the homozygote (Ml/Ml) of macular mutant mouse

The macular mutant mouse shows X-linked recessive inheritance and its hemizygote (Ml/y) is considered to be an appropriate model of Menkes kinky hair disease (MKHD). In this study the homozygote (Ml/Ml) was bred by coupling CuCl2-treated Ml/y with Ml/+ and was clinically and neuropathologically examined. The Ml/Ml had white fur color and curly whiskers from day 3, showed ataxia and tonic seizure on day 8 and gradually lost weight after day 10. It died with severe emaciation around day 15. These clinical features were improved by CuCl2 injection. Quantitative analysis showed that the dendritic arborization of the pyramidal cell in the treated Ml/Ml was delayed on days 14, 20, 30, 45 and 90 in comparison with that of the age-matched +/y. In the cerebellum of the Ml/Ml on day 14, some of the Purkinje cells showed abnormal changes such as somal sprouts, spine-like structures on the surface of the soma and stem dendrites, thick stem dendrites, multiple focal swellings of the stem and distal dendrites, reduction in the size of dendritic trees and axonal focal swellings. These changes were gradually improved in the Ml/Ml with CuCl2 treatment after day 20, with the exception of the multiple focal swellings of the stem and distal dendrites. The dendritic focal swelling gradually decreased after day 45. These clinical and neuropathological features of the Ml/Ml are almost same as those of the Ml/y. In our mutant mouse, when the treated Ml/Ml is coupled with the treated Ml/y all offspring from the Ml/Ml are genetically Ml/y or Ml/Ml. Our study indicates that these fetal mice may be useful for studying the pathological and biochemical condition of prenatal MKHD.

The cytoskeleton of the human cerebellar cortex: an immunohistochemical study of normal and pathological material

Monoclonal antibodies to non-phosphorylated and phosphorylated neurofilaments, as well as monoclonal and polyclonal antibodies to other cytoskeletal elements, were applied to the study of the cerebellar cortex of normal and pathological human material. The methods proved to be applicable to formalin fixed paraffin embedded tissue, provided the period of formalin fixation was short. The main difference between normal and pathological material was found in Purkinje cells and their dendrites. While normal Purkinje perikarya and dendrites expressed only non-phosphorylated neurofilaments, reactive dendrites stained more intensely with antibodies to phosphorylated neurofilaments. Similar observations were made on the abnormal dendritic ramifications of the partially deafferented, hypertrophic, inferior olive. The significance of the appearance of phosphorylated neurofilament epitopes in abnormal dendrites remains unknown and requires further investigation.

Chromatolytic changes in the central nervous system of patients with the toxic oil syndrome

Five patients died of a severe neuromyopathy months after the ingestion of adulterated rapeseed oil. These patients were selected for this study due to the presence of striking chromatolytic lesions in symmetric and scattered nuclei of the brain stem, including the locus coeruleus, midline raphe, lateral reticular nuclei of the medulla and cuneate nuclei. Two of the five cases, in addition to these topographic levels of involvement, had remarkable chromatolysis, vacuolar degeneration and heavy silver impregnation of the swollen perykarya and proximal dendrites in the nuclei of the basis pontis. In this paper we analyze the features of the chromatolytic lesion and suggest that the neuronal pathology observed in these cases is an example of irreversible chromatolysis involving vacuolization and filamentous proliferation as final events of the chromatolytic process. The cause of the cell degeneration in the toxic oil syndrome (TOS) is yet undetermined. Chromatolysis in this disease may be the result of a neurotoxic action of the toxic factor in the adulterated oil.

Abnormal arborizations of Purkinje cell dendrites in Creutzfeldt-Jakob disease: a manifestation of neuronal plasticity?

A case is presented of the ataxic variety of Creutzfeldt-Jakob disease with particular reference to the cerebellar cortex. The main features were loss of granule cells, subtotal in the vermis, severe in the lateral lobes, mild to moderate loss of Purkinje cells and preservation of tangential and basket fibres. The Purkinje cell dendrites showed malorientation and hypertrophy of the primary and secondary branches, the so-called "antler" or "staghorn" deformity. These findings indicate that remodelling of the dendritic tree may start early in the course of the disease even in adults, the total length of history in this case being eight months. They do not throw any additional light on the pathogenesis of the dendritic abnormalities, in particular on the controversy whether they are a non-specific response of the Purkinje cell to a variety of noxious agents or a reaction to partial deafferentation. The authors favour the latter hypothesis.