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Copper deficiency, or hypocupremia, is defined either as insufficient
copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
to meet the needs of the body, or as a serum copper level below the normal range. Symptoms may include fatigue, decreased red blood cells, early greying of the hair, and neurological problems presenting as
numbness Hypoesthesia or numbness is a common side effect of various medical conditions that manifests as a reduced sense of touch or sensation, or a partial loss of sensitivity to sensory stimuli. In everyday speech this is generally referred to as num ...
, tingling, muscle weakness, and
ataxia Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of ...
. The neurodegenerative syndrome of copper deficiency has been recognized for some time in ruminant animals, in which it is commonly known as " swayback". Copper deficiency can manifest in parallel with
vitamin B12 Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. It ...
and other nutritional deficiencies.


Overview

The most common cause of copper deficiency is a remote gastrointestinal surgery, such as
gastric bypass surgery Gastric bypass surgery refers to a technique in which the stomach is divided into a small upper pouch and a much larger lower "remnant" pouch and then the small intestine is rearranged to connect to both. Surgeons have developed several differ ...
, due to
malabsorption Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety ...
of copper, or
zinc toxicity Zinc toxicity is a medical condition involving an overdose on, or toxic overexposure to, zinc. Such toxicity levels have been seen to occur at ingestion of greater than 50 mg of zinc. Excessive absorption of zinc can suppress copper and iron ...
. On the other hand,
Menkes disease Menkes disease (MNK), also known as Menkes syndrome, is an X-linked recessive disorder caused by mutations in genes coding for the copper-transport protein ATP7A, leading to copper deficiency. Characteristic findings include kinky hair, growth ...
is a genetic disorder of copper deficiency involving a wide variety of symptoms that is often fatal. Copper is required for the functioning of many enzymes, such as
cytochrome c oxidase The enzyme cytochrome c oxidase or Complex IV, (was , now reclassified as a translocasEC 7.1.1.9 is a large transmembrane protein complex found in bacteria, archaea, and mitochondria of eukaryotes. It is the last enzyme in the respiratory elect ...
, which is complex IV in the mitochondrial electron transport chain,
ceruloplasmin Ceruloplasmin (or caeruloplasmin) is a ferroxidase enzyme that in humans is encoded by the ''CP'' gene. Ceruloplasmin is the major copper-carrying protein in the blood, and in addition plays a role in iron metabolism. It was first described in 1 ...
, Cu/Zn superoxide dismutase, and in
amine oxidase An amine oxidase is an enzyme that catalyzes the oxidative cleavage of alkylamines into aldehydes and ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictoge ...
s. These enzyme catalyze reactions for
oxidative phosphorylation Oxidative phosphorylation (UK , US ) or electron transport-linked phosphorylation or terminal oxidation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing chemical energy in order to produce adenosine tri ...
, iron transportation, antioxidant and free radical scavenging and neutralization, and
neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, any main body part or target cell, may be another neuron, but could also be a gland or muscle cell. Neuro ...
synthesis, respectively. Diets vary in the amount of copper they contain, but may provide about 5 mg/day, of which only 20-50% is absorbed. The diet of the elderly may have a lower copper content than the recommended daily intake. Dietary copper can be found in
whole grain A whole grain is a grain of any cereal and pseudocereal that contains the endosperm, germ, and bran, in contrast to refined grains, which retain only the endosperm. As part of a general healthy diet, consumption of whole grains is associated w ...
cereal A cereal is any Poaceae, grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, Cereal germ, germ, and bran. Cereal Grain, grain crops are grown in greater quantit ...
s,
legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...
s,
oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not ...
s, organ meats (particularly
liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...
), cherries, dark chocolate,
fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...
s, leafy green vegetables,
nut Nut often refers to: * Nut (fruit), fruit composed of a hard shell and a seed, or a collective noun for dry and edible fruits or seeds * Nut (hardware), fastener used with a bolt Nut or Nuts may also refer to: Arts, entertainment, and media Co ...
s,
poultry Poultry () are domesticated birds kept by humans for their eggs, their meat or their feathers. These birds are most typically members of the superorder Galloanserae (fowl), especially the order Galliformes (which includes chickens, quails, a ...
,
prune A prune is a dried plum, most commonly from the European plum (''Prunus domestica''). Not all plum species or varieties can be dried into prunes. A prune is the firm-fleshed fruit (plum) of '' Prunus domestica'' varieties that have a high so ...
s, and
soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu an ...
products like
tofu Tofu (), also known as bean curd in English, is a food prepared by coagulating soy milk and then pressing the resulting curds into solid white blocks of varying softness; it can be ''silken'', ''soft'', ''firm'', ''extra firm'' or ''super f ...
. Copper deficiency can have many hematological consequences, such as
myelodysplasia A myelodysplastic syndrome (MDS) is one of a group of cancers in which immature blood cells in the bone marrow do not mature, and as a result, do not develop into healthy blood cells. Early on, no symptoms typically are seen. Later, symptoms may ...
,
anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...
, low white blood cell count, and low count of neutrophils (a type of white blood cell that is often called "the first line of defense" of the immune system). Copper deficiency has long been known as a cause of myelodysplasia (when a blood profile has indicators of possible future
leukemia Leukemia ( also spelled leukaemia and pronounced ) is a group of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or ' ...
development), but it was not until 2001 that copper deficiency was associated with neurological manifestations like
sensory ataxia Sensory ataxia is both a symptom and a sign in neurology. It is a form of ataxia (loss of coordination) caused not by cerebellar dysfunction but by loss of sensory input into the control of movement. Sensory ataxia is distinguished from cerebel ...
(irregular coordination due to
proprioceptive Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons ...
loss), spasticity, muscle weakness, and more rarely visual loss due to damage in the peripheral nerves,
myelopathy Myelopathy describes any neurologic deficit related to the spinal cord. The most common form of myelopathy in humans, ''Spinal cord compression, cervical spondylotic myelopathy (CSM)'', also called ''degenerative cervical myelopathy'', results fro ...
(disease of the spinal cord), and rarely
optic neuropathy Optic neuropathy is damage to the optic nerve from any cause. The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain. Damage and death of these nerve cells, or neurons, leads to characteristic featu ...
.


Signs and symptoms


Blood symptoms

The characteristic hematological (blood) effects of copper deficiency are
anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...
(which may be microcytic, normocytic or macrocytic) and
neutropenia Neutropenia is an abnormally low concentration of neutrophils (a type of white blood cell) in the blood. Neutrophils make up the majority of circulating white blood cells and serve as the primary defense against infections by destroying bacteria ...
.
Thrombocytopenia Thrombocytopenia is a condition characterized by abnormally low levels of platelets, also known as thrombocytes, in the blood. It is the most common coagulation disorder among intensive care patients and is seen in a fifth of medical patients a ...
(low blood
platelets Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby ini ...
) is unusual. The peripheral blood and
bone marrow aspirate Bone marrow examination refers to the pathology, pathologic analysis of samples of bone marrow obtained by bone marrow biopsy (often called trephine biopsy) and bone marrow aspiration. Bone marrow examination is used in the diagnosis of a number o ...
findings in copper deficiency can mimic
myelodysplastic syndrome A myelodysplastic syndrome (MDS) is one of a group of cancers in which immature blood cells in the bone marrow do not mature, and as a result, do not develop into healthy blood cells. Early on, no symptoms typically are seen. Later, symptoms may ...
.
Bone marrow aspirate Bone marrow examination refers to the pathology, pathologic analysis of samples of bone marrow obtained by bone marrow biopsy (often called trephine biopsy) and bone marrow aspiration. Bone marrow examination is used in the diagnosis of a number o ...
in both conditions may show
dysplasia Dysplasia is any of various types of abnormal growth or development of cells (microscopic scale) or organs (macroscopic scale), and the abnormal histology or anatomical structure(s) resulting from such growth. Dysplasias on a mainly microscopic ...
of blood cell precursors and the presence of ring sideroblasts (
erythroblast A nucleated red blood cell (NRBC), also known by several other names, is a red blood cell that contains a cell nucleus. Almost all vertebrate organisms have hemoglobin-containing cells in their blood, and with the exception of mammals, all of t ...
s containing multiple iron granules around the nucleus). Unlike most cases of myelodysplastic syndrome, the bone marrow aspirate in copper deficiency characteristically shows cytoplasmic
vacuoles A vacuole () is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic mo ...
within red and white cell precursors, and
karyotyping A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...
in cases of copper deficiency does not reveal cytogenetic features characteristic of myelodysplastic syndrome. Anemia and neutropenia typically resolve within six weeks of copper replacement.


Neurological symptoms

Copper deficiency can cause a wide variety of neurological problems including
myelopathy Myelopathy describes any neurologic deficit related to the spinal cord. The most common form of myelopathy in humans, ''Spinal cord compression, cervical spondylotic myelopathy (CSM)'', also called ''degenerative cervical myelopathy'', results fro ...
, peripheral
neuropathy Peripheral neuropathy, often shortened to neuropathy, is a general term describing disease affecting the peripheral nerves, meaning nerves beyond the brain and spinal cord. Damage to peripheral nerves may impair sensation, movement, gland, or o ...
, and
optic neuropathy Optic neuropathy is damage to the optic nerve from any cause. The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain. Damage and death of these nerve cells, or neurons, leads to characteristic featu ...
.


Myelopathy

Copper deficiency myelopathy in humans was discovered and first described by Schleper and Stuerenburg in 2001. They described a patient with a history of gastrectomy and partial colonic resection who presented with severe tetraparesis and painful paraesthesias and who was found on imaging to have dorsomedial cervical cord T2 hyperintensity. Upon further analysis, it was found that the patient had decreased levels of serum coeruloplasmin, serum copper, and CSF copper. The patient was treated with parenteral copper and the patient's paraesthesias did resolve. Since this discovery, there has been heightened and increasing awareness of copper-deficiency myelopathy and its treatment, and this disorder has been reviewed by Kumar. Patients typically present difficulty walking ( gait difficulty) caused by
sensory ataxia Sensory ataxia is both a symptom and a sign in neurology. It is a form of ataxia (loss of coordination) caused not by cerebellar dysfunction but by loss of sensory input into the control of movement. Sensory ataxia is distinguished from cerebel ...
(irregular muscle coordination) due to
dorsal column Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...
dysfunction or degeneration of the spinal cord (
myelopathy Myelopathy describes any neurologic deficit related to the spinal cord. The most common form of myelopathy in humans, ''Spinal cord compression, cervical spondylotic myelopathy (CSM)'', also called ''degenerative cervical myelopathy'', results fro ...
). Patients with ataxic gait have problems balancing and display an unstable wide walk. They often feel tremors in their torso, causing sideways jerks and lunges. In brain MRI, there is often an increased T2 signalling at the posterior columns of the spinal cord in patients with myelopathy caused by copper deficiency. T2 signalling is often an indicator of some kind of neurodegeneration. There are some changes in the spinal cord MRI involving the thoracic cord, the cervical cord or sometimes both. Copper deficiency myelopathy is often compared to subacute combined degeneration (SCD). Subacute combined degeneration is also a degeneration of the spinal cord, but instead
vitamin B12 Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. It ...
deficiency is the cause of the spinal degeneration. SCD also has the same high T2 signalling intensities in the posterior column as copper deficient patient in MRI imaging.


Peripheral neuropathy

Another common symptom of copper deficiency is
peripheral neuropathy Peripheral neuropathy, often shortened to neuropathy, is a general term describing disease affecting the peripheral nerves, meaning nerves beyond the brain and spinal cord. Damage to peripheral nerves may impair sensation, movement, gland, or or ...
, which is numbness or tingling that can start in the extremities and can sometimes progress radially inward towards the torso. In an Advances in Clinical Neuroscience & Rehabilitation (ACNR) published case report, a 69-year-old patient had progressively worsened neurological symptoms. These symptoms included diminished upper limb reflexes with abnormal lower limb reflexes, sensation to light touch and pin prick was diminished above the waist, vibration sensation was lost in the sternum, and markedly reduced
proprioception Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons ...
or sensation about the self's orientation. Many people with the neurological effects of copper deficiency complain about very similar or identical symptoms as the patient. This numbness and tingling poses danger for the elderly because it increases their risk of falling and injuring themselves. Peripheral
neuropathy Peripheral neuropathy, often shortened to neuropathy, is a general term describing disease affecting the peripheral nerves, meaning nerves beyond the brain and spinal cord. Damage to peripheral nerves may impair sensation, movement, gland, or o ...
can become very disabling leaving some patients reliant on wheelchairs or walking canes for mobility if there is a lack of correct diagnosis. Rarely can copper deficiency cause major disabling symptoms. The deficiency will have to be present for an extensive amount of time until such disabling conditions manifest.


Optic neuropathy

Some patients with copper deficiency have shown signs of vision and color loss. The vision is usually lost in the peripheral views of the eye. The bilateral vision loss is usually very gradual. An
optical coherence tomography Optical coherence tomography (OCT) is an imaging technique that uses low-coherence light to capture micrometer-resolution, two- and three-dimensional images from within optical scattering media (e.g., biological tissue). It is used for medica ...
(OCT) shows some nerve fiber layer loss in most patients, suggesting the vision loss and color vision loss was secondary to
optic neuropathy Optic neuropathy is damage to the optic nerve from any cause. The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain. Damage and death of these nerve cells, or neurons, leads to characteristic featu ...
or neurodegeneration.


Causes


Surgery

Bariatric surgery is a common cause of copper deficiency. Bariatric surgery, such as
gastric bypass surgery Gastric bypass surgery refers to a technique in which the stomach is divided into a small upper pouch and a much larger lower "remnant" pouch and then the small intestine is rearranged to connect to both. Surgeons have developed several differ ...
, is often used for weight control of the morbidly obese. The disruption of the intestines and stomach from the surgery can cause absorption difficulties not only as regards copper but also for iron and
vitamin B12 Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. It ...
and many other nutrients. The symptoms of copper deficiency
myelopathy Myelopathy describes any neurologic deficit related to the spinal cord. The most common form of myelopathy in humans, ''Spinal cord compression, cervical spondylotic myelopathy (CSM)'', also called ''degenerative cervical myelopathy'', results fro ...
may take up to decades to develop.


Zinc toxicity

Increased consumption of
zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
is another cause of copper deficiency.
Zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
is often used for the prevention or treatment of common colds and
sinusitis Sinusitis, also known as rhinosinusitis, is inflammation of the mucous membranes that line the sinuses resulting in symptoms that may include thick nasal mucus, a plugged nose, and facial pain. Other signs and symptoms may include fever, head ...
(inflammation of sinuses due to an infection), ulcers,
sickle cell disease Sickle cell disease (SCD) is a group of blood disorders typically inherited from a person's parents. The most common type is known as sickle cell anaemia. It results in an abnormality in the oxygen-carrying protein haemoglobin found in red b ...
,
celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barle ...
, memory impairment, and acne. Zinc is found in many common vitamin supplements and is also found in denture creams. Recently, several cases of copper deficiency myeloneuropathy were found to be caused by prolonged use of denture creams containing high quantities of zinc. A literature review found two cases of copper deficiency myelopathy secondary to parenteral zinc supplementation during chronic dialysis. Metallic zinc is the core of all United States currency coins, including copper-coated pennies. People who ingest a large number of coins will have elevated zinc levels, leading to zinc-toxicity-induced copper deficiency and the associated neurological symptoms. This was the case for a 57-year-old woman diagnosed with
schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
. The woman consumed over 600 coins, and started to show neurological symptoms such as unsteady gait and mild
ataxia Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of ...
.


Hereditary disorders

Menkes disease Menkes disease (MNK), also known as Menkes syndrome, is an X-linked recessive disorder caused by mutations in genes coding for the copper-transport protein ATP7A, leading to copper deficiency. Characteristic findings include kinky hair, growth ...
is a congenital disease that is a cause of copper deficiency. Menkes disease is a hereditary condition caused by a defective gene involved with the metabolism of copper in the body. Menkes disease involves a wide variety of symptoms including floppy muscle tone,
seizures An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or neural oscillation, synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much o ...
, abnormally low temperatures, and a peculiar steel color hair that feels very rough. Menkes disease is usually a fatal disease with most children dying within the first ten years of life.


Other

It is rarely suggested that excess iron supplementation causes copper deficiency
myelopathy Myelopathy describes any neurologic deficit related to the spinal cord. The most common form of myelopathy in humans, ''Spinal cord compression, cervical spondylotic myelopathy (CSM)'', also called ''degenerative cervical myelopathy'', results fro ...
. Another rarer cause of copper deficiency is
celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barle ...
, probably due to malabsorption in the intestines. Still, a large percentage, around 20%, of cases have unknown causes.


Pathophysiology

Copper functions as a prosthetic group, which permits electron transfers in key enzymatic pathways like the electron transport chain. electronic-book electronic- Copper is integrated in the enzymes
cytochrome c oxidase The enzyme cytochrome c oxidase or Complex IV, (was , now reclassified as a translocasEC 7.1.1.9 is a large transmembrane protein complex found in bacteria, archaea, and mitochondria of eukaryotes. It is the last enzyme in the respiratory elect ...
, which is involved in
cellular respiration Cellular respiration is the process by which biological fuels are oxidised in the presence of an inorganic electron acceptor such as oxygen to produce large amounts of energy, to drive the bulk production of ATP. Cellular respiration may be des ...
and
oxidative phosphorylation Oxidative phosphorylation (UK , US ) or electron transport-linked phosphorylation or terminal oxidation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing chemical energy in order to produce adenosine tri ...
, Cu/Zn dismutase, which is involved in
antioxidant Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubricant ...
defense, and many more listed in the table below.


Neurological


Cytochrome c oxidase

There have been several hypotheses about the role of copper and some of its neurological manifestations. Some suggest that disruptions in
cytochrome c oxidase The enzyme cytochrome c oxidase or Complex IV, (was , now reclassified as a translocasEC 7.1.1.9 is a large transmembrane protein complex found in bacteria, archaea, and mitochondria of eukaryotes. It is the last enzyme in the respiratory elect ...
, also known as Complex IV, of the electron transport chain is responsible for the spinal cord degeneration.


Methylation cycle

Another hypothesis is that copper deficiency myelopathy is caused by disruptions in the methylation cycle. The methylation cycle causes a transfer of a methyl group (-CH3) from methyltetrahydrofolate to a range of
macromolecules A macromolecule is a very large molecule important to biophysical processes, such as a protein or nucleic acid. It is composed of thousands of covalently bonded atoms. Many macromolecules are polymers of smaller molecules called monomers. The ...
by the suspected copper dependent enzyme
methionine synthase Methionine synthase also known as MS, MeSe, MTR is responsible for the regeneration of methionine from homocysteine. In humans it is encoded by the ''MTR'' gene (5-methyltetrahydrofolate-homocysteine methyltransferase). Methionine synthase forms ...
. This cycle is able to produce
purines Purine is a heterocyclic aromatic organic compound that consists of two rings ( pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines ...
, which are a component of DNA
nucleotide bases Nucleobases, also known as ''nitrogenous bases'' or often simply ''bases'', are nitrogen-containing biological compounds that form nucleosides, which, in turn, are components of nucleotides, with all of these monomers constituting the bas ...
, and also
myelin Myelin is a lipid-rich material that surrounds nerve cell axons (the nervous system's "wires") to insulate them and increase the rate at which electrical impulses (called action potentials) are passed along the axon. The myelinated axon can be ...
proteins. The spinal cord is surrounded by a layer of protective protein coating called myelin (see figure). When this methionine synthase enzyme is disrupted, the methylation decreases and myelination of the spinal cord is impaired. This cycle ultimately causes
myelopathy Myelopathy describes any neurologic deficit related to the spinal cord. The most common form of myelopathy in humans, ''Spinal cord compression, cervical spondylotic myelopathy (CSM)'', also called ''degenerative cervical myelopathy'', results fro ...
.


Hematological cause


Iron transportation

The
anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...
caused by copper deficiency is thought to be caused by impaired iron transport.
Hephaestin Hephaestin, also known as HEPH, is a protein which in humans is encoded by the ''HEPH'' gene. Function Hephaestin is involved in the metabolism and homeostasis of iron and possibly copper. It is a transmembrane copper-dependent ferroxidase resp ...
is a copper containing
ferroxidase Ferroxidase also known as Fe(II):oxygen oxidoreductase is an enzyme that catalyzes the oxidization of iron II to iron III: : 4 Fe2+ + 4 H+ + O2 ⇔ 4 Fe3+ + 2H2O Examples Human genes encoding proteins with ferroxidase activity include: * C ...
enzyme located in the duodenal muscosa that oxidizes iron and facilitates its transfer across the basolateral membrane into circulation. Another iron transporting enzyme is
ceruloplasmin Ceruloplasmin (or caeruloplasmin) is a ferroxidase enzyme that in humans is encoded by the ''CP'' gene. Ceruloplasmin is the major copper-carrying protein in the blood, and in addition plays a role in iron metabolism. It was first described in 1 ...
. This enzyme is required to mobilize iron from the reticuloendothelial cell to plasma. Ceruloplasmin also oxidizes iron from its ferrous state to the ferric form that is required for iron binding. Impairment in these copper dependent enzymes that transport iron may cause the secondary iron deficiency anemia. Another speculation for the cause of anemia is involving the mitochondrial enzyme
cytochrome c oxidase The enzyme cytochrome c oxidase or Complex IV, (was , now reclassified as a translocasEC 7.1.1.9 is a large transmembrane protein complex found in bacteria, archaea, and mitochondria of eukaryotes. It is the last enzyme in the respiratory elect ...
(complex IV in the electron transport chain). Studies have shown that animal models with impaired cytochrome c oxidase failed to synthesize
heme Heme, or haem (pronounced / hi:m/ ), is a precursor to hemoglobin, which is necessary to bind oxygen in the bloodstream. Heme is biosynthesized in both the bone marrow and the liver. In biochemical terms, heme is a coordination complex "consis ...
from
ferric In chemistry, iron(III) refers to the element iron in its +3 oxidation state. In ionic compounds (salts), such an atom may occur as a separate cation (positive ion) denoted by Fe3+. The adjective ferric or the prefix ferri- is often used to sp ...
iron at the normal rate. The lower rate of the enzyme might also cause the excess iron to clump, giving the heme an unusual pattern. This unusual pattern is also known as ringed sideroblastic anemia cells.


Cell growth halt

The cause of
neutropenia Neutropenia is an abnormally low concentration of neutrophils (a type of white blood cell) in the blood. Neutrophils make up the majority of circulating white blood cells and serve as the primary defense against infections by destroying bacteria ...
is still unclear; however, the arrest of maturing myelocytes, or
neutrophil Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying ...
precursors, may cause the
neutrophil Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying ...
deficiency.


Zinc intoxication

Zinc intoxication may cause
anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...
by blocking the absorption of copper from the stomach and duodenum. Zinc also upregulates the expression of
chelator Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are ...
metallothionein Metallothionein (MT) is a family of cysteine-rich, low molecular weight (MW ranging from 500 to 14000 Da) proteins. They are localized to the membrane of the Golgi apparatus. MTs have the capacity to bind both physiological (such as zinc, copp ...
in
enterocytes Enterocytes, or intestinal absorptive cells, are simple columnar epithelial cells which line the inner surface of the small and large intestines. A glycocalyx surface coat contains digestive enzymes. Microvilli on the apical surface increase it ...
, which are the majority of cells in the intestinal epithelium. Since copper has a higher affinity for metallothionein than zinc, the copper will remain bound inside the enterocyte, which will be later eliminated through the lumen. This mechanism is exploited therapeutically to achieve negative balance in
Wilson's disease Wilson's disease is a genetic disorder in which excess copper builds up in the body. Symptoms are typically related to the brain and liver. Liver-related symptoms include vomiting, weakness, fluid build up in the abdomen, swelling of the legs, ...
, which involves an excess of copper.


Diagnosis

The diagnosis of copper deficiency may be supported by a person's report of compatible signs and symptoms, findings from a thorough physical examination, and supportive laboratory evidence. Low levels of copper and
ceruloplasmin Ceruloplasmin (or caeruloplasmin) is a ferroxidase enzyme that in humans is encoded by the ''CP'' gene. Ceruloplasmin is the major copper-carrying protein in the blood, and in addition plays a role in iron metabolism. It was first described in 1 ...
in the serum are consistent with the diagnosis as is a low 24 hour urine copper level. Additional supportive bloodwork findings also include
neutropenia Neutropenia is an abnormally low concentration of neutrophils (a type of white blood cell) in the blood. Neutrophils make up the majority of circulating white blood cells and serve as the primary defense against infections by destroying bacteria ...
and
anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...
. MRI imaging may demonstrate increased T2 signal of the
dorsal column–medial lemniscus pathway The dorsal column–medial lemniscus pathway (DCML) (also known as the posterior column-medial lemniscus pathway, PCML) is a sensory pathway of the central nervous system that conveys sensations of fine touch, vibration, two-point discriminatio ...
s.


Treatment

Copper deficiency is a very rare disease and is often misdiagnosed several times by physicians before concluding the deficiency of copper through differential diagnosis (copper serum test and
bone marrow biopsy Bone marrow examination refers to the pathologic analysis of samples of bone marrow obtained by bone marrow biopsy (often called trephine biopsy) and bone marrow aspiration. Bone marrow examination is used in the diagnosis of a number of conditio ...
are usually conclusive in diagnosing copper deficiency). On average, patients are diagnosed with copper deficiency around 1.1 years after their first symptoms are reported to a physician. Copper deficiency can be treated with either oral copper supplementation or
intravenous Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...
copper. If zinc intoxication is present, discontinuation of zinc may be sufficient to restore copper levels back to normal, but this usually is a very slow process. People with zinc intoxication will usually have to take copper supplements in addition to ceasing zinc consumption. Hematological manifestations are often quickly restored back to normal. The progression of the neurological symptoms will be stopped and sometimes improved with appropriate treatment, but residual neurological disability is common.


See also

*
Copper in health Copper is an essential trace element that is vital to the health of all living things (plants, animals and microorganisms). In humans, copper is essential to the proper functioning of organs and metabolic processes. The human body has complex h ...
* Copper deficiency and excess health conditions (non-genetic)


References

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Online Medical Video
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External links

{{Medical resources , DiseasesDB = 3094 , ICD10 = {{ICD10, E, 61, 0, e, 50 , ICD9 = {{ICD9, 275.1 , ICDO = , OMIM = 121270 , MedlinePlus = , eMedicineSubj = , eMedicineTopic = , MeshID = {{Nutritional pathology {{Elements in biology {{DEFAULTSORT:Copper Deficiency Mineral deficiencies
Deficiency A deficiency is generally a lack of something. It may also refer to: *A deficient number, in mathematics, a number ''n'' for which ''σ''(''n'') < 2''n'' * Animal diseases