Copper is a component of many body proteins; almost all of the body’s copper is bound to copper proteins.
Copper deficiency may be acquired or inherited. (See also Overview of Mineral Deficiency and Toxicity.)
Acquired Copper Deficiency
If the genetic mechanisms controlling copper metabolism are normal, dietary deficiency rarely causes clinically significant copper deficiency. Causes include
- Severe childhood protein deficiency
- Persistent infantile diarrhea (usually associated with a diet limited to milk)
- Severe malabsorption (as in sprue or cystic fibrosis)
- Gastric surgery (where vitamin B12 deficiency may also be present)
- Excessive zinc intake
Deficiency may cause neutropenia, impaired bone calcification, myelopathy, neuropathy, and hypochromic anemia not responsive to iron supplements.
Diagnosis of acquired copper deficiency is based on low serum levels of copper and ceruloplasmin, although these tests are not always reliable.
Treatment of acquired copper deficiency is directed at the cause, and copper 1.5 to 3 mg/day orally (usually as copper sulfate) is given.
Inherited Copper Deficiency
Inherited copper deficiency occurs in male infants who inherit a mutant X-linked gene. Incidence is about 1 in 100,000 to 250,000 live births. Copper is deficient in the liver, serum, and essential copper proteins, including cytochrome-c oxidase, ceruloplasmin, and lysyl oxidase.
(See also Wilson Disease.)
Symptoms and Signs
Symptoms of inherited copper deficiency are severe intellectual disability, vomiting, diarrhea, protein-losing enteropathy, hypopigmentation, bone changes, and arterial rupture; the hair is sparse, steely, or kinky.
Most affected children die by age 10 years.
- Serum copper and ceruloplasmin levels
Diagnosis of inherited copper deficiency is based on low copper and ceruloplasmin levels in serum. Because early diagnosis and treatment seem to result in a better prognosis, the disorder is ideally detected before age 2 weeks. However, diagnostic accuracy of these tests is limited. Thus, other tests are being developed.
- Copper histidine
Parenteral copper is usually given as copper histidine 250 mcg subcutaneous injection twice a day to age 1 year, then 250 mcg subcutaneously once/day until age 3 years; monitoring of kidney function is essential during treatment.
Despite early treatment, many children have abnormal neurodevelopment.