Menkes kinky-hair disease. A report on its pathology

Disorders of metal metabolism

Trace elements are chemical elements needed in minute amounts for normal physiology. Some of the physiologically relevant trace elements include iodine, copper, iron, manganese, zinc, selenium, cobalt and molybdenum. Of these, some are metals, and in particular, transition metals. The different electron shells of an atom carry different energy levels, with those closest to the nucleus being lowest in energy. The number of electrons in the outermost shell determines the reactivity of such an atom. The electron shells are divided in sub-shells, and in particular the third shell has s, p and d sub-shells. Transition metals are strictly defined as elements whose atom has an incomplete d sub-shell. This incomplete d sub-shell makes them prone to chemical reactions, particularly redox reactions. Transition metals of biologic importance include copper, iron, manganese, cobalt and molybdenum. Zinc is not a transition metal, since it has a complete d sub-shell. Selenium, on the other hand, is strictly speaking a nonmetal, although given its chemical properties between those of metals and nonmetals, it is sometimes considered a metalloid. In this review, we summarize the current knowledge on the inborn errors of metal and metalloid metabolism.

Bone marrow from blotchy mice is dispensable to regulate blood copper and aortic pathologies but required for inflammatory mediator production in LDLR-deficient mice during chronic angiotensin II infusion

BACKGROUND

The blotchy mouse caused by mutations of ATP7A develops low blood copper and aortic aneurysm and rupture. Although the aortic pathologies are believed primarily due to congenital copper deficiencies in connective tissue, perinatal copper supplementation does not produce significant therapeutic effects, hinting additional mechanisms in the symptom development, such as an independent effect of the ATP7A mutations during adulthood.

METHODS

We investigated if bone marrow from blotchy mice contributes to these symptoms. For these experiments, bone marrow from blotchy mice (blotchy marrow group) and healthy littermate controls (control marrow group) was used to reconstitute recipient mice (irradiated male low-density lipoprotein receptor -/- mice), which were then infused with angiotensin II (1,000 ng/kg/min) for 4 weeks.

RESULTS

By using Mann-Whitney U test, our results showed that there was no significant difference in the copper concentrations in plasma and hematopoietic cells between these 2 groups. And plasma level of triglycerides was significantly reduced in blotchy marrow group compared with that in control marrow group (P < 0.05), whereas there were no significant differences in cholesterol and phospholipids between these 2 groups. Furthermore, a bead-based multiplex immunoassay showed that macrophage inflammatory protein (MIP)-1β, monocyte chemotactic protein (MCP)-1, MCP-3, MCP-5, tissue inhibitor of metalloproteinases (TIMP)-1, and vascular endothelial growth factor (VEGF)-A production was significantly reduced in the plasma of blotchy marrow group compared with that in control marrow group (P < 0.05). More important, although angiotensin II infusion increased maximal external aortic diameters in thoracic and abdominal segments, there was no significant difference in the aortic diameters between these 2 groups. Furthermore, aortic ruptures, including transmural breaks of the elastic laminae in the abdominal segment and lethal rupture in the thoracic segment, were observed in blotchy marrow group but not in control marrow group; however, there was no significant difference in the incidence of aortic ruptures between these 2 groups (P = 0.10; Fisher's exact test).

CONCLUSIONS

Overall, our study indicated that the effect of bone marrow from blotchy mice during adulthood is dispensable in the regulation of blood copper, plasma cholesterol and phospholipids levels, and aortic pathologies, but contributes to a reduction of MIP-1β, MCP-1, MCP-3, MCP-5, TIMP-1, and VEGF-A production and triglycerides concentration in plasma. Our study also hints that bone marrow transplantation cannot serve as an independent treatment option.

"From sheep to babe"--Menkes disease

A four-month-old boy presented with a new onset focal seizure lasting 18 minutes. During the seizure, his head and eyes were deviated to the left, and he assumed a fencing posture to the left with pursing of his lips. He had been unwell for one week, with episodes of poor feeding, during which he would become unresponsive, limp and stare for a few seconds. Developmentally he was delayed. He was not yet rolling, and he had only just begun to lift his head in prone position. He could grasp but was not reaching or bringing his hands together at the midline. He was cooing but not laughing. His past medical history was significant for term delivery with fetal distress and meconium staining. He was flat and blue at birth, with birth weight of 3.5 kg, and Apgar scores of 1 at one minute, 4 at 5 minutes, and 8 at 10 minutes. He required resuscitation with positive pressure ventilation for two minutes, and then had no further postnatal complications. Family history was remarkable for a paternal cousin with cortical malformation, epilepsy, and developmental delay. His mother and maternal grandmother had migraine headaches and fibromyalgia.

Neuropathology of occipital horn syndrome

Occipital horn syndrome, formerly known as Ehlers-Danlos syndrome type IX or X-linked cutis laxa, is an allelic variant of Menkes' syndrome. Although the clinical symptomatology and systemic pathology findings have been well described in occipital horn syndrome, the neuropathology has not previously been reported. A kindred affected by the X-linked occipital horn syndrome is followed at the University of Alabama at Birmingham. A severely mentally retarded dysmorphic man, who died at the age of 26 years, never gained the ability to walk or talk. Among other findings at autopsy, the patient had the skeletal anomalies previously described with occipital horn syndrome. Neuropathologic findings included neovascularization and extreme reduplication of the cerebral arteries, in conjunction with cystic medial degeneration; bilateral cerebellar hypoplasia; focal cortical dysplasia, and cerebellar heterotopias. These findings are similar to those seen in the brains of patients with Menkes' syndrome, which is not surprising, given the known phenotypic overlap and the proven allelism of occipital horn syndrome with classic Menkes' syndrome.

Metabolic and molecular bases of Menkes disease and occipital horn syndrome

Menkes disease and occipital horn syndrome (OHS) are related disorders of copper transport that involve abnormal neurodevelopment, connective tissue problems, and often premature death. Location of the gene responsible for these conditions on the X chromosome was indicated by pedigree analysis from the time of these syndromes' earliest descriptions. Characterization of an affected female with an X-autosomal translocation was used to identify the Menkes/OHS gene, which encodes a highly evolutionarily conserved, copper-transporting P-type ATPase. The gene normally is expressed in nearly all human tissues, and it localizes to the trans-Golgi network of cells. However, in over 70% of Menkes and OHS patients studied, expression of this gene has been demonstrated to be abnormal. Major gene deletions detectable by Southern blotting account for 15-20% of patients, and an interesting spectrum of other mutations is evident among 58 families whose precise molecular defects have been reported as of this writing. The center region of the gene seems particularly prone to mutation, and those that influence mRNA processing and splicing appear to be relatively common. Further advances in understanding the molecular and cell biological mechanisms involved in normal copper transport may ultimately yield new and better approaches to the management of these disorders.

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

The macular mouse is a mutant mouse with a defect in copper transport and an X-linked recessive inheritance. Its hemizygote (Ml/y) is considered to be an appropriate model fo Menkes kinky hair disease (MKHD). In this study, homozygote (Ml/Ml) were bred by coupling CuCl2-treated Ml/y with heterozygote (Ml/+). Both Ml/Ml and Ml/y die around day 15 of age. However, treatment with CuCl2 enables them to live until adulthood. The brains of Ml/Ml were chronologically examined by light and electron microscopy. In the non-treated Ml/Ml, abnormal mitochondria increased in number in the cerebral cortical neurons and in the cerebellar Purkinje cells from day 7 to 14 of age. In the treated Ml/Ml, the administration of CuCl2 improved the abnormality of the mitochondria in the cerebrum by day 20, but those in the Purkinje cells remained until day 60. Flattened cisterns and intracytoplasmic inclusions were also observed in the Purkinje cells of treated Ml/Ml. These ultrastructural changes were quite similar to those observed in the Ml/y. Our mutant mice (treated Ml/Ml), when they are coupled with treated Ml/y, can give birth to offspring, all of which will be genetically Ml/y or Ml/Ml. These fetal mice will be very helpful for studying the pathological and biochemical condition of prenatal MKHD.

Neuronal and vascular disorders of the brain and spinal cord in Menkes kinky hair disease

A 3 2/12-year-old boy had recurrent seizures, chronic respiratory infection, and delayed physical and mental development. He also had low plasma copper content typical of Menkes syndrome. Autopsy showed marked neuronal loss and gliosis in most areas of the cerebral and cerebellar cortices, midbrain, pons, and medulla. The spinal cord showed severe demyelination in both ascending (spinocerebellar) and descending (lateral corticospinal) tracts from the cervical to the sacral level. In addition to these neuronal lesions, both the meningeal and parenchymal arterial and venous branches were remarkably dilated in the brain and spinal cord. Our previous study of this case showed abnormal perivascular innervation and abnormal axonal swelling of the postganglionic adrenergic fibers elsewhere in the body. The metabolic disorder caused by copper deficiency induces severe neuronal degeneration that is apparently exaggerated by extensive and progressive vascular abnormality.

[Menkes syndrome: review of the pathogenesis apropos of a clinico-pathological case]

The authors report a case of Menkes' syndrome, probably the first one described in Brazil. The patient, a 15-month-old boy, showed pili torti, early progressive psychomotor deterioration and seizures. Serum levels of ceruloplasmin and copper were very low. Neuroradiological and roentgenological examinations revealed diffuse cerebral atrophy, arterial changes and bone abnormalities. At the post-mortem examination the more consistent findings were cerebral atrophy, neuronal loss in the thalamus and above all cerebellar cortical lesions. The disease has a sex-linked recessive inheritance and is believed to be caused by an inborn error of copper metabolism, perhaps subordinated to changes of proteins which carry copper to different tissues. The relevant literature in relation to the pathogenesis is reviewed.

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

The neuropathological findings in two siblings with Menkes' disease were compared with representative material obtained from lambs suffering from swayback (enzootic ataxia). The aim of the study was to demonstrate the similarity of lesions in a genetic and a nutritional form of copper deficiency in support of the view that all lesions in Menkes' disease could be ascribed to simple hypocupraemia. All lesions of Menkes' disease were shown to have their counterpart in swayback, with exception of the abnormal arborisations of the Purkinje cell dendrites. These have often been interpreted as malformations and cited in evidence of the prenatal origin of the cerebral lesions. They are, however, non-specific and similar lesions have been reported in conditions arising in later life. While there is abundant collateral evidence of disturbed copper metabolism in utero, the problem of the prenatal versus postnatal origin of cerebral damage remains unresolved.

Menkes' syndrome: an updated review

Menkes' syndrome is an X-linked recessive multisystem disease which is usually fatal prior to 5 years of age. Though originally felt to be a disorder of copper deficiency, it now appears to be a copper storage disease, with the observed defects resulting from inappropriate systemic copper distribution. Disorders in the metabolism of metallothionein, a metalloprotein involved in cellular copper transport, may be the primary defect in this syndrome. This review summarizes the relevant clinical and pathologic findings seen in this condition to date. It also describes some of the abnormalities in the metabolism of copper and metallothionein in these infants.

Mitochondrial abnormalities in Menkes' kinky hair disease (MKHD). Electron-microscopic study of the brain from an autopsy case

The brain of an autopsy case of Menkes' kinky hair disease (MKHD), after routine histological examination, was studied extensively by electron microscopy, particularly the mitochondrial alteration. There were widespread mitochondrial abnormalities, including enlargement with tubulo-vesiculated cristae, swelling, and dense body formation and occasional accumulation of glycogen within mitochondria, in addition to increased numbers of mitochondria in some neurons. These abnormalities of mitochondria were present in decreasing severity in the following: Purkinje cells, neurons of the molecular and granule cell layers of the cerebellum, and neurons of the cerebral cortex, globus pallidus, lateral nuclei of the thalamus, caudate nucleus, and the myelinated axons in the white matter. This distribution and the degree of mitochondrial abnormalities in the various structures of the brain were compared with those of degenerative lesions in the respective structures. The comparison disclosed that there was a positive correlation between the two. The mitochondrial enlargement and swelling as in the present study had been well documented in the brain of the brindled mouse; mitochondrial dense bodies had also been reported in previous case reports of MKHD by other authors. The present study strongly suggests that the mitochondrial disease is an essential abnormality and may be responsible for the progressive degeneration of the CNS in MKHD.

The effect of copper supplementation on the concentration of copper in the brain of the brindled mouse

The brindled mutant mouse is a useful model to study Menkes kinky-hair syndrome. The metabolic dysfunctions in both human and rodent are related to insufficient levels of bioavailable copper. Recently, copper supplementation therapy has been able both to prevent the appearance of various neuropathological changes and to prolong the life of these mutant mice. The optimum conditions for supplementation have been shown to be two intraperitoneal injections on postnatal days 7 and 10. The present study reports on the brain copper concentrations before, during and after the intraperitoneal copper therapy. The results demonstrate that postnatal days 7 and 10 correspond to two important epochs in copper homoeostasis. The supplementation therapy seems to provide sufficient bioavailable copper to respond to the needs of the animal at these crucial time points. The results are discussed in terms of their importance to the human copper disorder.

Copper deficiency suppresses the immune response of mice

Mice fed a purified diet low in copper display anemia, hypoceruloplasminemia, depressed concentrations of liver copper, and elevated concentrations of liver iron. An impaired humoral-mediated immune response (decreased numbers of antibody-producing cells) is observed in mice with severe as well as marginal copper deficiency. The magnitude of this impairment is highly correlated with the degree of functional copper deficiency (hypoceruloplasminemia).

Brindled mottled mouse: morphological changes of brain and visceral organs in hemizygous males following copper supplementation

Intraperitoneal injections of cupric chloride prevent neuronal degeneration in the hemizygous brindled mottle mouse, MO br/Y, a murine model of kinky hair syndrome (KHS) in humans. At 6-9 months after two i.p. injections, the brain of MO br/Y revealed slightly increased amounts of lipofuscin pigments in the cerebral cortical neurons, cytoplasmic inclusions in the thalamic neurons, and axonal spheroid formation in the tuber cinereum, cerebellum and brain stem. Increased numbers of mitoses, bizarre hyperchromatic giant nuclei, and numerous clear vacuoles were frequently seen in the proximal renal tubular epithelium. Numerous myelin figures were conspicuous features in these epithelial cells at ultrastructural level. Such changes were not found in the littermate controls but in the heterozygous brindled mottled mouse, MO br/ +, identical changes were noted in equal or even higher frequency. These observations suggest that cupric chloride injections effectively modify the expression of the genetic defect in MO br/ Y.

Neuronal degeneration in the brain of the brindled mouse. I. Chromological studies on the long-surviving group

Brindled mutant mouse (MObr) is clinically closely similar to kinky hair syndrome (KHS) in humans. Hemizygous males (MObr/Y) of this mutant usually cannot survive beyond the 15th -- 16th postnatal day. However, some were found to survive into the adult life. Extensive neuronal degeneration in the cerebral cortex was a prominent neuropathological feature of MObr/Y (Yajima and Suzuki, 1979a). In the long surviving one, however, such neuronal degeneration gradually disappeared and cortical neuronal loss and axonal degeneration of the underlying white matter were the predominant neuropathological features. which are closely similar to those of KHS, in particular in those patients who survive for more than 1 year. On the basis of our observations on the brain of MObr/Y mice, we hypothesized the possible chronological events on the development of neuropathological lesions in KHS in humans.