Zinc, Copper and Selenium Deficiency
On this page
Direct answer
Zinc, copper and selenium deficiencies are trace element disorders, each with a syndrome that examiners expect you to recognise. Zinc deficiency classically causes acrodermatitis enteropathica, copper deficiency causes anaemia, neutropenia and myeloneuropathy, often after bariatric surgery, and selenium deficiency is linked to Keshan disease, a cardiomyopathy seen in selenium-poor regions.
What you must remember
- Acrodermatitis enteropathica: an autosomal recessive zinc absorption defect causing periorificial and acral dermatitis, alopecia and diarrhoea, which responds to zinc.
- Lifelong therapy: the inherited form needs lifelong zinc supplementation, since the absorption defect persists.
- Zinc in childhood diarrhoea: zinc with oral rehydration salts is part of standard management of diarrhoea in Indian children under national guidance.
- Zinc excess: high zinc intake induces intestinal metallothionein, which traps copper and produces copper deficiency.
- Copper after bariatric surgery: Roux-en-Y gastric bypass can cause anaemia, neutropenia and a dorsal column myeloneuropathy.
- Menkes disease: an X-linked ATP7A defect causing copper deficiency, with kinky hair and neurodegeneration, contrasted with Wilson disease, which is copper excess.
- Keshan disease: a selenium-responsive cardiomyopathy in children and young women of selenium-poor regions, named after an endemic area in China.
- Selenium function: selenium is part of glutathione peroxidase and of the deiodinases that activate thyroid hormone.
Matching each trace element to its syndrome
Trace element questions are answered by the syndrome and its cause, and the table links the two. Each element has a characteristic enzyme or transporter role that explains its clinical picture.
| Element | Classic syndrome | Typical cause |
|---|---|---|
| Zinc | Acrodermatitis enteropathica | Inherited absorption defect, malnutrition |
| Copper | Anaemia, neutropenia, myeloneuropathy | Bariatric surgery, excess zinc |
| Selenium | Keshan disease | Low intake from selenium-poor soil |
| Copper (inherited) | Menkes disease | ATP7A mutation |
Acquired copper deficiency is a common trace element problem after gastric bypass, so copper should be checked in unexplained cytopenias. Wilson disease is the opposite disorder, with copper excess, and examiners often use it as a distractor. Excess zinc induces intestinal metallothionein, which traps copper, so high zinc intake can cause copper deficiency.
Selenium acts through glutathione peroxidase and the deiodinases, and its deficiency is recalled as the regional syndrome, Keshan disease. Zinc and copper are therefore read together, because excess zinc disturbs copper absorption.
Traps with trace element vignettes
Most errors come from confusing copper excess with copper deficiency, or from ignoring the setting of the vignette.
- Trap: labelling every copper problem as Wilson disease Correct: Wilson disease is copper excess, while copper deficiency presents with anaemia and myeloneuropathy after bariatric surgery or excess zinc.
- Trap: stopping zinc once the rash settles in acrodermatitis enteropathica Correct: the inherited defect persists, so zinc is continued lifelong with monitoring.
- Trap: choosing selenium for any dilated cardiomyopathy vignette Correct: Keshan disease needs a selenium-poor setting and typically affects children or young women, so geography and age are the clues.
Frequently asked questions
Which zinc deficiency syndrome is inherited?
Acrodermatitis enteropathica is the inherited zinc deficiency, caused by an autosomal recessive defect in zinc absorption. It presents with periorificial and acral dermatitis, alopecia and diarrhoea, and zinc supplementation corrects the skin disease.
How does Menkes disease differ from Wilson disease?
Menkes disease is an X-linked defect in the ATP7A copper transporter that causes copper deficiency, with kinky hair and neurodegeneration. Wilson disease is an autosomal recessive defect in the ATP7B transporter that causes copper excess, with hepatic and neurological features.
What is Keshan disease?
Keshan disease is a cardiomyopathy seen in children and young women living in selenium-poor areas, and it is strongly linked to selenium deficiency. It causes cardiac dilatation and heart failure, and selenium supplementation is the preventive measure used in endemic regions.
What causes copper deficiency after bariatric surgery?
Copper deficiency after bariatric surgery arises from reduced absorption in the small intestine, particularly after Roux-en-Y gastric bypass. Excess zinc intake, often from supplements, also blocks copper absorption, so both should be considered in patients with unexplained anaemia or neuropathy.