Brachial artery aneurysms in Menkes disease

True Brachial Aneurysm in an Older Female Patient. A Case Report and Review of Literature

INTRODUCTION

Brachial artery aneurysms constitute 0.5% of peripheral aneurysms. These can be true or secondary to trauma or arteriovenous fistulas. These present as an asymptomatic pulsatile mass or may cause symptoms due to compression of adjacent neurological structures.

CASE REPORT

We present a review of the literature on clinical, histological, and therapeutic characteristics of true brachial aneurysms, motivated by the case of a 67-year-old woman with an asymptomatic pulsatile mass dependent on the brachial artery of the left arm who underwent open surgical correction with resection of the aneurysmal sac and interposition of great saphenous vein graft with adequate postoperative results.

The molecular and cellular basis of copper dysregulation and its relationship with human pathologies

Copper (Cu) is an essential micronutrient required for the activity of redox-active enzymes involved in critical metabolic reactions, signaling pathways, and biological functions. Transporters and chaperones control Cu ion levels and bioavailability to ensure proper subcellular and systemic Cu distribution. Intensive research has focused on understanding how mammalian cells maintain Cu homeostasis, and how molecular signals coordinate Cu acquisition and storage within organs. In humans, mutations of genes that regulate Cu homeostasis or facilitate interactions with Cu ions lead to numerous pathologic conditions. Malfunctions of the Cu⁺ -transporting ATPases ATP7A and ATP7B cause Menkes disease and Wilson disease, respectively. Additionally, defects in the mitochondrial and cellular distributions and homeostasis of Cu lead to severe neurodegenerative conditions, mitochondrial myopathies, and metabolic diseases. Cu has a dual nature in carcinogenesis as a promotor of tumor growth and an inducer of redox stress in cancer cells. Cu also plays role in cancer treatment as a component of drugs and a regulator of drug sensitivity and uptake. In this review, we provide an overview of the current knowledge of Cu metabolism and transport and its relation to various human pathologies.

Recurrent brachial artery aneurysm repair in a child managed with Gore-Tex conduit reinforcement

Pediatric nonaortic arterial aneurysms are uncommon diagnoses and can be affiliated with underlying conditions, which include neurofibromatosis I, Ehlers-Danlos type IV syndrome, Kawasaki disease, Marfan syndrome, and Loeys-Dietz, polyarteritis nodosa, as well as Klippel-Trenauny syndrome. The standard of care has been early surgical excision and arterial reconstruction when indicated. This report details a case of recurrent brachial artery aneurysm in a 2-year-old boy despite multiple attempts at excision and reconstruction. Such recurrences were seen as rapidly as 3 months postoperatively. Ultimately, a Gore-Tex conduit was used to reinforce a reversed saphenous vein graft repair. There has been no evidence of recurrent disease during the 18-month follow-up period.

Inhibition of lysyl oxidase stimulates TGF-β signaling and metalloproteinases-2 and -9 expression and contributes to the disruption of ascending aorta in rats: protection by propylthiouracil

Mutations in lysyl oxidase (LOX) genes cause severe vascular anomalies in mice and humans. LOX activity can be irreversibly inhibited by the administration of β-aminoproprionitrile (BAPN). We investigated the mechanisms underlying the damage to the ascending thoracic aorta induced by LOX deficiency and evaluated whether 6-propylthiouracil (PTU) can afford protection in rats. BAPN administration caused disruption of the ascending aortic wall, increased the number of apoptotic cells, stimulated TGF-β signaling (increase of nuclear p-SMAD2 staining), and up-regulated the expression of metalloproteinases-2 and -9. In BAPN-treated animals, PTU reduced apoptosis, p-SMAD2 staining, MMP-2, and -9 expression, and markedly decreased the damage to the aortic wall. Our results suggest that, as in some heritable vascular diseases, enhanced TGF-β signaling and upregulation of MMP-2 and -9 can contribute to the pathogenesis of ascending aorta damage caused by LOX deficiency. We have also shown that PTU, a drug already in clinical use, protects against the effects of LOX inhibition. MMP-2 and -9 might be potential targets of new therapeutic strategies for the treatment of vascular diseases caused by LOX deficiency.

The molecular mechanisms of copper metabolism and its roles in human diseases

Copper is an essential element in cells; it can act as either a recipient or a donor of electrons, participating in various reactions. However, an excess of copper ions in cells is detrimental as these copper ions can generate free radicals and increase oxidative stress. In multicellular organisms, copper metabolism involves uptake, distribution, sequestration, and excretion, at both the cellular and systemic levels. Mammalian enterocytes take in bioavailable copper ions from the diet in a Ctr1-dependent manner. After incorporation, cuprous ions are delivered to ATP7A, which pumps Cu⁺ from enterocytes into the blood. Copper ions arrive at the liver through the portal vein and are incorporated into hepatocytes by Ctr1. Then, Cu⁺ can be secreted into the bile or the blood via the Atox1/ATP7B/ceruloplasmin route. In the bloodstream, this micronutrient can reach peripheral tissues and is again incorporated by Ctr1. In peripheral tissue cells, cuprous ions are either sequestrated by molecules such as metallothioneins or targeted to utilization pathways by chaperons such as Atox1, Cox17, and CCS. Copper metabolism must be tightly controlled in order to achieve homeostasis and avoid disorders. A hereditary or acquired copper unbalance, including deficiency, overload, or misdistribution, may cause or aggravate certain diseases such as Menkes disease, Wilson disease, neurodegenerative diseases, anemia, metabolic syndrome, cardiovascular diseases, and cancer. A full understanding of copper metabolism and its roles in diseases underlies the identification of novel effective therapies for such diseases.

Management of upper extremity aneurysms: a systematic review

INTRODUCTION

The aim of this paper is to provide recommendations for diagnosis and management of arterial or venous aneurysms of the upper extremity.

EVIDENCE ACQUISITION

A systematic review of the Medline and Cockrane databases was performed from 1988 to 2019 by a combined strategy of MeSh terms.

EVIDENCE SYNTHESIS

One-hundred-forty-four publications were identified: 111 addressing arterial aneurysms and 33 addressing venous aneurysms. A total of 162 cases of arterial aneurysms, mostly brachial aneurysms (34.0% of cases) and 40 cases of venous aneurysms, mostly located in the forearm (60.0% of cases) were reported. For both types of aneurysms, most common presentation was the perception of a mass (56.3% for arterial one and 87.5% for venous one), but thromboembolic complication (46.7%), paresthesia (16.5%) or rupture (6.4%) could be observed in the setting of arterial aneurysms, while arm swelling (27.5%), neurological symptoms (12.5%), pulmonary embolism (10.0%) or rupture (2.5%) could occur in the setting of venous aneurysms. DUS was performed as first imaging modality for both settings, followed but CTA and MRA, especially in arterial aneurysms, to evaluate distal emboli and surrounding vasculature. Surgical treatment was mostly based on excision of the aneurysms with revascularization for arterial aneurysms (77.2%) and resection without reconstruction for the venous one (85.0%). Complications occurred in 10.5% of the cases of arterial aneurysms, none occurred after venous aneurysm resection.

CONCLUSIONS

Prompt diagnosis and appropriate preoperative imaging are mandatory in order to offer the best treatment modality. Open resection with revascularization seems to be the treatment of choice for arterial aneurysms, although endovascular procedures became more popular. Venous aneurysms require excision without revascularization.

Emergent embolization of a ruptured splenic artery aneurysm complicating Menkes disease

We report a 7-year-old boy with Menkes disease complicated by rupture of a large splenic artery aneurysm. The aneurysm was successfully embolized with microcoils and n-butyl cyanoacrylate. Further angiographic evaluation revealed marked tortuosity of mesenteric and lower extremity vasculature, including the femoral arteries bilaterally, without aneurysm formation. The patient has since been evaluated annually with computed tomography angiography and there have been no additional vascular complications of his disease during 3-year follow up.

Imaging in cutis laxa syndrome caused by a dominant negative ALDH18A1 mutation, with hypotheses for intracranial vascular tortuosity and wide perivascular spaces

The autosomal dominant progeroid form of cutis laxa is a recently identified multiple congenital anomaly disorder characterized by thin, wrinkled skin, a progeroid appearance, intra-uterine growth retardation, postnatal growth restriction, psychomotor developmental delay, microcephaly, cataract, hypotonia and contractures. De novo heterozygous mutations in ALDH18A1 have been described in this condition. We present neuroimaging abnormalities in three patients. One patient had intracranial arterial and venous tortuosity, widened ventricular and extra-axial cerebrospinal fluid (CSF) spaces, wide perivascular spaces and increased T2 signal intensity in the cerebral white matter over time. The second patient had vascular tortuosity. The third patient had prominent ventricular and extra-axial cerebrospinal fluid (CSF) spaces on CT. We propose an embryological mechanism for the development of intracranial vascular tortuosity and discuss the anatomical basis of wide perivascular spaces in relation to this syndrome. Although we do not know the clinical implications of these cerebral vascular anomalies, we suggest inclusion of neuroimaging in the baseline evaluation of these patients.

Recurrent spontaneous subserosal hematoma of ileum causing intestinal obstruction in a patient with menkes disease: A case report

BACKGROUND

Menkes disease (MD) is a disorder of copper metabolism due to ATP7A gene mutation that leads to severe copper deficiency. Deformed blood vessels can be found in many parts of the body, and intracranial hematoma is generally reported.

METHODS

We report a Taiwanese boy with MD who had recurrent spontaneous subserosal hematoma of ileum presenting as intestinal obstruction, with the 2 episodes 23 months apart. The patient returned to the usual physical status after surgical removal of the hematoma.

RESULTS

The defective copper metabolism causes dysfunction of a plenty of copper-dependent enzymes, giving rise to unique kinky hair appearance, progressive neurodegeneration, and connective tissue abnormalities. To our knowledge, this is the first report on recurrent subserosal hemorrhage of intestine in MD.

CONCLUSION

Owing to the fragile structure of blood vessels, subserosal hematoma should be considered when patients with MD having intestinal obstruction.

Pediatric nonaortic arterial aneurysms

OBJECTIVE

Pediatric arterial aneurysms are extremely uncommon. Indications for intervention remain poorly defined and treatments vary. The impetus for this study was to better define the contemporary surgical management of pediatric nonaortic arterial aneurysms.

METHODS

A retrospective analysis was conducted of 41 children with 61 aneurysms who underwent surgical treatment from 1983 to 2015 at the University of Michigan. Arteries affected included: renal (n = 26), femoral (n = 7), iliac (n = 7), superior mesenteric (n = 4), brachial (n = 3), carotid (n = 3), popliteal (n = 3), axillary (n = 2), celiac (n = 2), ulnar (n = 2), common hepatic (n = 1), and temporal (n = 1). Intracranial aneurysms and aortic aneurysms treated during the same time period were not included in this study. Primary outcomes analyzed were postoperative complications, mortality, and freedom from reintervention.

RESULTS

The study included 27 boys and 14 girls, with a median age of 9.8 years (range, 2 months-18 years) and a weight of 31.0 kg (range, 3.8-71 kg). Multiple aneurysms existed in 14 children. Obvious factors that contributed to aneurysmal formation included: proximal juxta-aneurysmal stenoses (n = 14), trauma (n = 12), Kawasaki disease (n = 4), Ehlers-Danlos type IV syndrome (n = 1), and infection (n = 1). Preoperative diagnoses were established using arteriography (n = 23), magnetic resonance angiography (n = 6), computed tomographic arteriography (n = 5), or ultrasonography (n = 7), and confirmed during surgery. Indications for surgery included risk of expansion and rupture, potential thrombosis or embolization of aneurysmal thrombus, local soft tissue and nerve compression, and secondary hypertension in the case of renal artery aneurysms. Primary surgical techniques included: aneurysm resection with reanastomsis, reimplantation, or angioplastic closure (n = 16), interposition (n = 10) or bypass grafts (n = 2), ligation (n = 9), plication (n = 8), endovascular occlusion (n = 3), and nephrectomy (n = 4) in cases of unreconstructable renal aneurysmal disease. Later secondary operations were required to treat stenoses at the site of the original aneurysm repairs (n = 2) and new aneurysmal development (n = 1). Postoperative follow-up averaged 47 months (range, 1-349 months). No major perioperative morbidity and no mortality was encountered in this experience.

CONCLUSIONS

Pediatric arterial aneurysms represent a complex disease that affects multiple vascular territories. Results of the current series suggest that individualized surgical treatment, ranging from simple ligations to major arterial reconstructions, was durable and can be undertaken with minimal risk.

Mottled Mice and Non-Mammalian Models of Menkes Disease

Menkes disease is a multi-systemic copper metabolism disorder caused by mutations in the X-linked ATP7A gene and characterized by progressive neurodegeneration and severe connective tissue defects. The ATP7A protein is a copper (Cu)-transporting ATPase expressed in all tissues and plays a critical role in the maintenance of copper homeostasis in cells of the whole body. ATP7A participates in copper absorption in the small intestine and in copper transport to the central nervous system (CNS) across the blood-brain-barrier (BBB) and blood–cerebrospinal fluid barrier (BCSFB). Cu is essential for synaptogenesis and axonal development. In cells, ATP7A participates in the incorporation of copper into Cu-dependent enzymes during the course of its maturation in the secretory pathway. There is a high degree of homology (>80%) between the human ATP7A and murine Atp7a genes. Mice with mutations in the Atp7a gene, called mottled mutants, are well-established and excellent models of Menkes disease. Mottled mutants closely recapitulate the Menkes phenotype and are invaluable for studying Cu-metabolism. They provide useful models for exploring and testing new forms of therapy in Menkes disease. Recently, non-mammalian models of Menkes disease, Drosophila melanogaster and Danio rerio mutants were used in experiments which would be technically difficult to carry out in mammals.

Impaired osteogenesis in Menkes disease-derived induced pluripotent stem cells

Introduction

Bone abnormalities, one of the primary manifestations of Menkes disease (MD), include a weakened bone matrix and low mineral density. However, the molecular and cellular mechanisms underlying these bone defects are poorly understood.

Methods

We present in vitro modeling for impaired osteogenesis in MD using human induced pluripotent stem cells (iPSCs) with a mutated ATP7A gene. MD-iPSC lines were generated from two patients harboring different mutations.

Results

The MD-iPSCs showed a remarkable retardation in CD105 expression with morphological anomalies during development to mesenchymal stem cells (MSCs) compared with wild-type (WT)-iPSCs. Interestingly, although prolonged culture enhanced CD105 expression, mature MD-MSCs presented with low alkaline phosphatase activity, reduced calcium deposition in the extracellular matrix, and downregulated osteoblast-specific genes during osteoblast differentiation in vitro. Knockdown of ATP7A also impaired osteogenesis in WT-MSCs. Lysyl oxidase activity was also decreased in MD-MSCs during osteoblast differentiation.

Conclusions

Our findings indicate that ATP7A dysfunction contributes to retardation in MSC development and impairs osteogenesis in MD.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0147-5) contains supplementary material, which is available to authorized users.

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.

Neurodevelopment and brain growth in classic Menkes disease is influenced by age and symptomatology at initiation of copper treatment

Menkes disease is an X-linked recessive disorder of brain copper metabolism caused by mutations in an essential mammalian copper transport gene, ATP7A. Untreated affected individuals suffer failure to thrive and neurodevelopmental delays that usually commence at 6-8 weeks of age. Death by age three years is typical. While provision of working copies of ATP7A to the brain by viral vectors is a promising strategy under development, the only treatment currently available is subcutaneous copper injections. These can normalize circulating blood levels and may replete brain copper depending on the molecular context, e.g., the severity of ATP7A mutation and potential presence of mosaicism. In this paper, we summarize somatic growth and neurodevelopmental outcomes for 60 subjects enrolled in a recently concluded phase I/II clinical trial of copper histidine for Menkes disease (ClinicalTrials.gov Identifier: NCT00001262). Primary outcomes indicate highly statistically significant improvements in gross motor, fine motor/adaptive, personal-social, and language neurodevelopment in the cohort of subjects who received early treatment prior to onset of symptoms (n=35). Correlating with these findings, quantitative parameters of somatic growth indicated statistically significant greater growth in head circumference for the initially asymptomatic group, whereas weight and height/length at age three years (or at time of death) did not differ significantly. Mortality at age 3 was higher (50%) in subjects older and symptomatic when treatment commenced compared to the asymptomatic group (28.6%). We conclude that early copper histidine for Menkes disease is safe and efficacious, with treatment outcomes influenced by the timing of intervention, and ATP7A mutation.

Translational research investigations on ATP7A: an important human copper ATPase

In more than 40 years since copper deficiency was delineated in pediatric subjects with Menkes disease, remarkable advances in our understanding of the clinical, biochemical, and molecular aspects of the human copper transporter ATP7A have emerged. Mutations in the gene encoding this multitasking molecule are now implicated in at least two other distinctive phenotypes: occipital horn syndrome and ATP7A-related isolated distal motor neuropathy. Several other novel inherited disorders of copper metabolism have been identified in the past several years, aided by advances in human gene mapping and automated DNA sequencing. In this paper, I review the history and evolution of our understanding of disorders caused by impaired ATP7A function, and outline future challenges.

Delayed rupture of a pseudoaneurysm in the brachial artery of a burn reconstruction patient

A brachial artery pseudoaneurysm is a rare but serious condition that can be limb threatening. A number of reports have found that it may be the result of damage to the blood vessels around the brachial artery, either directly or indirectly, due to trauma or systemic diseases. We present our experience of delayed pseudoaneurysm rupture of the brachial artery in a rehabilitation patient with burns of the upper extremity who underwent fasciotomy and musculocutaneous flap coverage. We also provide a review of the brachial artery pseudoaneurysm.

Inborn errors of copper metabolism

Two copper-transporting ATPases are essential for mammalian copper homeostasis: ATP7A, which mediates copper uptake in the gastrointestinal tract and copper delivery to the brain, and ATP7B, which mediates copper excretion by the liver into bile. Mutations in ATP7A may cause three distinct X-linked conditions in infants, children, or adolescents: Menkes disease, occipital horn syndrome (OHS), and a newly identified allelic variant restricted to motor neurons called X-linked distal hereditary motor neuropathy. These three disorders show variable neurological findings and ages of onset. Menkes disease presents in the first several months of life with failure to thrive, developmental delay, and seizures. OHS features more subtle developmental delays, dysautonomia, and connective tissue abnormalities beginning in early childhood. ATP7A-related distal motor neuropathy presents even later, often not until adolescence or early adulthood, and involves a neurological phenotype that resembles Charcot-Marie-Tooth disease, type 2. These disorders may be treatable through copper replacement or ATP7A gene therapy. In contrast, mutations in ATP7B cause a single known phenotype, Wilson disease, an autosomal recessive trait that results from copper overload rather than deficiency. Dysarthria, dystonia, tremor, gait abnormalities, and psychiatric problems may be presenting symptoms, at ages from 10 to 40 years. Excellent treatment options exist for Wilson disease, based on copper chelation. In the past 2 years (2012-2013), three new autosomal recessive copper metabolism conditions have been recognized: 1) Huppke-Brendel syndrome caused by mutations in an acetyl CoA transporter needed for acetylation of one or more copper proteins, 2) CCS deficiency caused by mutations in the copper chaperone to SODI, and 3) MEDNIK syndrome, which revealed that mutations in the σ1A subunit of adaptor protein complex 1 (AP-1) have detrimental effects on trafficking of ATP7A and ATP7B.

Cervical spine anomalies in Menkes disease: a radiologic finding potentially confused with child abuse

BACKGROUND

Menkes disease is an X-linked recessive disorder of copper transport caused by mutations in ATP7A, a copper-transporting ATPase. Certain radiologic findings reported in this condition overlap with those caused by child abuse. However, cervical spine defects simulating cervical spine fracture, a known result of nonaccidental pediatric trauma, have not been reported previously in this illness.

OBJECTIVE

To assess the frequency of cervical spine anomalies in Menkes disease after discovery of an apparent C2 posterior arch defect in a child participating in a clinical trial.

MATERIALS AND METHODS

We examined cervical spine radiographs obtained in 35 children with Menkes disease enrolled in a clinical trial at the National Institutes of Health Clinical Center.

RESULTS

Four of the 35 children with Menkes disease had apparent C2 posterior arch defects consistent with spondylolysis or incomplete/delayed ossification.

CONCLUSION

Defects in C2 were found in 11% of infants and young children with Menkes disease. Discovery of cervical spine defects expands the spectrum of radiologic findings associated with this condition. As with other skeletal abnormalities, this feature simulates nonaccidental trauma. In the context of Menkes disease, suspicions of child abuse should be considered cautiously and tempered by these findings to avoid unwarranted accusations.

ATP7A-related copper transport diseases-emerging concepts and future trends

This Review summarizes recent advances in understanding copper-transporting ATPase 1 (ATP7A), and examines the neurological phenotypes associated with dysfunction of this protein. Involvement of ATP7A in axonal outgrowth, synapse integrity and neuronal activation underscores the fundamental importance of copper metabolism to neurological function. Defects in ATP7A cause Menkes disease, an infantile-onset, lethal condition. Neonatal diagnosis and early treatment with copper injections enhance survival in patients with this disease, and can normalize clinical outcomes if mutant ATP7A molecules retain small amounts of residual activity. Gene replacement rescues a mouse model of Menkes disease, suggesting a potential therapeutic approach for patients with complete loss-of-function ATP7A mutations. Remarkably, a newly discovered ATP7A disorder-isolated distal motor neuropathy-has none of the characteristic clinical or biochemical abnormalities of Menkes disease or its milder allelic variant occipital horn syndrome (OHS), instead resembling Charcot-Marie-Tooth disease type 2. These findings indicate that ATP7A has a crucial but previously unappreciated role in motor neuron maintenance, and that the mechanism underlying ATP7A-related distal motor neuropathy is distinct from Menkes disease and OHS pathophysiology. Collectively, these insights refine our knowledge of the neurology of ATP7A-related copper transport diseases and pave the way for further progress in understanding ATP7A function.

Favorably skewed X-inactivation accounts for neurological sparing in female carriers of Menkes disease

Classical Menkes disease is an X-linked recessive neurodegenerative disorder caused by mutations in ATP7A, which is located at Xq13.1-q21. ATP7A encodes a copper-transporting P-type ATPase and plays a critical role in development of the central nervous system. With rare exceptions involving sex chromosome aneuploidy or X-autosome translocations, female carriers of ATP7A mutations are asymptomatic except for subtle hair and skin abnormalities, although the mechanism for this neurological sparing has not been reported. We studied a three-generation family in which a severe ATP7A mutation, a 5.5-kb genomic deletion spanning exons 13 and 14, segregated. The deletion junction fragment was amplified from the proband by long-range polymerase chain reaction and sequenced to characterize the breakpoints. We screened at-risk females in the family for this junction fragment and analyzed their X-inactivation patterns using the human androgen-receptor (HUMARA) gene methylation assay. We detected the junction fragment in the proband, two obligate heterozygotes, and four of six at-risk females. Skewed inactivation of the X chromosome harboring the deletion was noted in all female carriers of the deletion (n = 6), whereas random X-inactivation was observed in all non-carriers (n = 2). Our results formally document one mechanism for neurological sparing in female carriers of ATP7A mutations. Based on review of X-inactivation patterns in female carriers of other X-linked recessive diseases, our findings imply that substantial expression of a mutant ATP7A at the expense of the normal allele could be associated with neurologic symptoms in female carriers of Menkes disease and its allelic variants, occipital horn syndrome, and ATP7A-related distal motor neuropathy.

Somatic mosaicism in Menkes disease suggests choroid plexus-mediated copper transport to the developing brain

The primary mechanism of copper transport to the brain is unknown, although this process is drastically impaired in Menkes disease, an X-linked neurodevelopmental disorder caused by mutations in an evolutionarily conserved copper transporter, ATP7A. Potential central nervous system entry routes for copper include brain capillary endothelial cells that originate from mesodermal angioblasts and form the blood-brain barrier, and the choroid plexuses, which derive from embryonic ectoderm, and form the blood-cerebrospinal fluid barrier. We exploited a rare (and first reported) example of somatic mosaicism for an ATP7A mutation to shed light on questions about copper transport into the developing brain. In a 20-month-old Menkes disease patient evaluated before copper treatment, blood copper, and catecholamine concentrations were normal, whereas levels in cerebrospinal fluid were abnormal and consistent with his neurologically severe phenotype. We documented disparate levels of mosaicism for an ATP7A missense mutation, P1001L, in tissues derived from different embryonic origins; allele quantitation showed P1001L in approximately 27% of DNA samples from blood cells (mesoderm-derived) and 88% from cultured fibroblasts (ectoderm-derived). These findings imply that the P1001L mutation in the patient preceded formation of the three primary embryonic lineages at gastrulation, with the ectoderm layer ultimately harboring a higher percentage of mutation-bearing cells than mesoderm or endoderm. Since choroid plexus epithelia are derived from neuroectoderm, and brain capillary endothelial cells from mesodermal angioblasts, the clinical and biochemical findings in this infant support a critical role for the blood-CSF barrier (choroid plexus epithelia) in copper entry to the developing brain.

Histopathology of an iliac aneurysm in a case of Menkes disease

In Menkes disease, arterial tortuosity is frequent, whereas true aneurysms are rare. Here, we report aneurysmal pathology occurring in an infant with Menkes disease. An iliac aneurysm was diagnosed in a 2-month-old boy and attributed to Menkes syndrome on the basis of plasma copper deficiency. Samples of the aneurysmal wall were taken during surgery for histopathological analysis. As in other forms of aneurysm, the arterial wall was characterized by smooth muscle cell (SMC) disappearance, linked to SMC apoptosis and oxidative stress, areas of mucoid degeneration, and extracellular matrix breakdown, including disappearance of elastic fibers and presence of abnormal collagen.

Management of brachial artery aneurisms in infants

Brachial artery aneurisms in children under 1 year of age are very rare. The main risk is distal ischaemic complication. We report four infants suffering from brachial artery aneurism of unknown origin. In all cases we used Doppler ultrasonography to validate the clinical diagnosis. Pre-operative vascular check-up was negative for other aneurismal location. Surgical excision with direct end-to-end anastomosis was possible in one patient; the others required interposition of an autologous venous graft. At discharge, patients were given oral aspirin for a few weeks. Histological examination revealed one pseudoaneurism and three true aneurisms. There were no complications either postoperatively or at 18 months follow-up. Arterial ligation might be indicated in only two situations: aneurism distal to profunda brachii artery, or chronic wall thrombus completely occluding (but distal perfusion through a neovascularization must be assessed first on angiography). Surgical excision with arterial reconstruction is the standard treatment. Endovascular treatment is not suitable because such a procedure in an infant would generate excessive radiation exposure, and a risk of stent migration with limb growth. In the case of an initial isolated and idiopathic presentation, or of false aneurism, clinical follow-up at 1 year is sufficient. In the case of secondary lesion, multiple initial presentation or relapse, life-long follow-up with repeated corporal imaging should be performed.

Function and regulation of human copper-transporting ATPases

Copper-transporting ATPases (Cu-ATPases) ATP7A and ATP7B are evolutionarily conserved polytopic membrane proteins with essential roles in human physiology. The Cu-ATPases are expressed in most tissues, and their transport activity is crucial for central nervous system development, liver function, connective tissue formation, and many other physiological processes. The loss of ATP7A or ATP7B function is associated with severe metabolic disorders, Menkes disease, and Wilson disease. In cells, the Cu-ATPases maintain intracellular copper concentration by transporting copper from the cytosol across cellular membranes. They also contribute to protein biosynthesis by delivering copper into the lumen of the secretory pathway where metal ion is incorporated into copper-dependent enzymes. The biosynthetic and homeostatic functions of Cu-ATPases are performed in different cell compartments; targeting to these compartments and the functional activity of Cu-ATPase are both regulated by copper. In recent years, significant progress has been made in understanding the structure, function, and regulation of these essential transporters. These studies raised many new questions related to specific physiological roles of Cu-ATPases in various tissues and complex mechanisms that control the Cu-ATPase function. This review summarizes current data on the structural organization and functional properties of ATP7A and ATP7B as well as their localization and functions in various tissues, and discusses the current models of regulated trafficking of human Cu-ATPases.

Internal jugular phlebectasia in Menkes disease

Pediatric neck masses should trigger a high index of suspicion for certain genetic disorders of connective tissue. To highlight this, we report on three infants with Menkes disease, an inherited disorder of copper transport, who developed large, unilateral neck masses at between 7 and 17 months of age. All were identified in imaging studies as internal jugular phlebectasia. The masses, which enlarged on crying or exertion, have remained clinically benign in these patients for 20, 17, and 2 months, respectively. While arterial tortuosity and aneurysms have been reported often in Menkes disease, venous phlebectasia has rarely been described. We speculate that low activity of the copper-dependent enzyme, lysyl oxidase, leading to reduced tensile strength in the deep cervical fascia comprising the carotid sheath may predispose to internal jugular phlebectasia in these individuals. Improved survival and neurological outcomes in infants with Menkes disease due to advances in early diagnosis and treatment may be associated with recognition of novel clinical stigmata of this condition such as internal jugular phlebectasia.

Copper deficiency

PURPOSE OF REVIEW

Reports of the neurologic findings in adults with acquired copper deficiency as well as the development of novel models for Menkes disease have permitted a greater understanding of the role of copper in the central nervous system. A role of mitochondrial copper homeostasis in cellular energy metabolism suggests roles for this metal in cellular differentiation and biochemical adaptation.

RECENT FINDINGS

Acquired copper deficiency in adults is reported with increasing frequency, often without any identifiable cause. Chemical genetic studies identified a zebrafish model of Menkes disease that can be used for high-throughput therapeutics and revealed a hierarchy of copper distribution during development. Studies in mice reveal that the copper transport protein Ctr1 is essential for intestinal copper absorption and suggest a unique role for copper in axonal extension, excitotoxic cell death and synaptic plasticity in the central nervous system. Lastly, recent biochemical studies indicate a central role for the mitochondrial matrix in cellular copper metabolism.

SUMMARY

The recent developments in our understanding of copper deficiency and copper homeostasis outlined in this review provide an exciting platform for future investigations intended to elucidate the role of copper in central nervous system development and disease.