Copper deficiency
Copper deficiency | |
---|---|
Other names | Hypocupremia |
Ring Sideroblast smear, a sign of copper deficiency in the blood. | |
Specialty | Endocrinology |
Risk factors | Alcoholism, gastric bypass surgery |
Copper deficiency, or hypocupremia, is defined either as insufficient copper to meet the needs of the body, or as a serum copper level below the normal range.[1] Symptoms may include fatigue, decreased red blood cells, early greying of the hair, and neurological problems presenting as numbness, tingling, muscle weakness, and ataxia.[2] The neurodegenerative syndrome of copper deficiency has been recognized for some time in ruminant animals, in which it is commonly known as "swayback".[3] Copper deficiency can manifest in parallel with vitamin B12 and other nutritional deficiencies.[2]
Overview
The most common cause of copper deficiency is a remote gastrointestinal surgery, such as gastric bypass surgery, due to malabsorption of copper, or zinc toxicity. On the other hand, Menkes disease is a genetic disorder of copper deficiency involving a wide variety of symptoms that is often fatal.[4]
Copper is required for the functioning of many enzymes, such as
Copper deficiency can have many hematological consequences, such as
Signs and symptoms
Blood symptoms
The characteristic hematological (blood) effects of copper deficiency are
The peripheral blood and
Anemia and neutropenia typically resolve within six weeks of copper replacement.[8]
Neurological symptoms
Copper deficiency can cause a wide variety of neurological problems including
Myelopathy
Copper deficiency myelopathy in humans was discovered and first described by Schleper and Stuerenburg in 2001.[9] 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 (
In brain MRI, there is often an increased
Peripheral neuropathy
Another common symptom of copper deficiency is
Optic neuropathy
Some patients with copper deficiency have shown signs of vision and color loss.[13] The vision is usually lost in the peripheral views of the eye.[13] The bilateral vision loss is usually very gradual.[13][15] An optical coherence tomography (OCT) shows some nerve fiber layer loss in most patients, suggesting the vision loss and color vision loss was secondary to optic neuropathy or neurodegeneration.[13]
Causes
Surgery
Bariatric surgery is a common cause of copper deficiency.[3][6] Bariatric surgery, such as gastric bypass surgery, 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 and many other nutrients.[3] The symptoms of copper deficiency myelopathy may take up to decades to develop.
Zinc toxicity
Increased consumption of
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. The woman consumed over 600 coins, and started to show neurological symptoms such as unsteady gait and mild ataxia.[17]
Hereditary disorders
Other
It is rarely suggested that excess iron supplementation causes copper deficiency myelopathy.[3] Another rarer cause of copper deficiency is
Pathophysiology
Copper functions as a prosthetic group, which permits electron transfers in key enzymatic pathways like the electron transport chain.[3][2][19] Copper is integrated in the enzymes cytochrome c oxidase, which is involved in cellular respiration and oxidative phosphorylation, Cu/Zn dismutase, which is involved in antioxidant defense, and many more listed in the table below.[2]
Group | Enzyme | Function |
---|---|---|
Oxidases | Flavin-containing amine oxidase | Metabolism of neurotransmitters: and some dietary amines |
Protein-lysine-6-oxidase (lysyl oxidase) | Connective tissue synthesis- cross-linking of collagen and elastin | |
Copper-containing amine oxidase (a family of enzymes which includes primary-amine oxidase and diamine oxidase) | Oxidation of biogenic amines including histamines, putrescine, cadaverine , and xenobiotic amines
| |
Cytochrome c oxidase | Oxidative phosphorylation, electron transport in the mitochondrial membrane
| |
Superoxide dismutase (Cu/Zn dismutase) | Antioxidant and free radical scavenger, oxidizes dangerous superoxides to safer hydrogen peroxide
| |
Ferroxidase I (ceruloplasmin) | Iron transport-oxidation of Fe2+ to Fe3+, copper storage and transport, antioxidant and free radical neutralizer | |
Hephaestin (ferroxidase) | Iron transport and oxidation of Fe2+ to Fe3+ in intestinal cells to enable iron uptake | |
Monooxygenases | Dopamine beta-monooxygenase |
Conversion of dopamine to norepinephrine |
Peptidylglycine monooxygenase | Peptide amidation of alpha-terminal carboxylic acid group of glycine
| |
Monophenol monooxygenase (Tyrosinase) | Melanin synthesis | |
Methylation Cycle | Methionine synthase | Transfer of methyl group from methyltetrahydrofolate to tetrahydrofolate for purine synthesis
|
Adenosylhomocysteinase (S-Adenosyl-L-homocysteine) | Regeneration of homocysteine from adenosylhomocyesteine (S-Adenosyl-L-homocysteine) in the methylation cycle |
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, also known as Complex IV, of the electron transport chain is responsible for the spinal cord degeneration.[3][10]
Methylation cycle
Another hypothesis is that copper deficiency myelopathy is caused by disruptions in the
Hematological cause
Iron transportation
The
Cell growth halt
The cause of neutropenia is still unclear; however, the arrest of maturing myelocytes, or neutrophil precursors, may cause the neutrophil deficiency.[2][6]
Zinc intoxication
Zinc intoxication may cause
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 in the serum are consistent with the diagnosis as is a low 24 hour urine copper level.[20] Additional supportive bloodwork findings also include neutropenia and anemia.[20] MRI imaging may demonstrate increased T2 signal of the dorsal column–medial lemniscus pathways.[20]
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
See also
- Copper in health
- Copper deficiency and excess health conditions (non-genetic)
References
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- ^ doi:10.1039/B816011M.
- ^ "Copper Information: Benefits, Deficiencies, Food Sources".
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- ^ PMID 18472229.
- ^ Ataxic gait demonstration. Online Medical Video
- ^ S2CID 21488713.
- ^ PMID 20451943.
- ^ a b Jaiser, S.R.; Duddy, R. (2007). "Copper deficiency masquerading as subacute combined degeneration of the cord and myelodysplastic syndrome" (PDF). ACNR: Advances in Clinical Neuroscience and Rehabilitation. 7 (3): 20–21. Archived from the original (PDF) on 2020-08-01. Retrieved 2010-11-29.
- ^ S2CID 28373986.
- ^ PMID 19732792.
- PMID 18180130.
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- ^ S2CID 21401030.