Rare genetic disorder highlights importance of selenium

Nov 16, 2010
Importance of selenium highlighted by rare genetic disorder

A rare genetic disorder has highlighted the importance to human health of selenium, a little known trace element. The discovery, reported today in the Journal of Clinical Investigation, may also shed light on the role of free radicals - highly reactive molecules which can cause cellular damage - in the body.

An international team of researchers at the University of Cambridge, funded principally by the Wellcome Trust, studied two individuals who were first identified on the basis of abnormal , but subsequently found to also have low levels of selenium in the body.

Selenium is found in relatively high doses in foods such as Brazil nuts. Although toxic in large amounts, as a trace element it is essential to in animals, including humans. In the body, it is incorporated as the amino acid selenocysteine into some proteins (known as selenoproteins).

The individuals identified by the researchers were found to have a particular variant of the gene SECISBP2 which meant that their bodies were unable to produce most of the 25 known human selenoproteins. As a consequence of selenoprotein deficiencies in particular tissues, they developed disorders such as male and muscular dystrophy ().

Other features of the disorder were due to loss of a subset of selenoproteins that are antioxidant enzymes. When the skin is exposed to ultraviolet light, free radicals are produced in the body. Ordinarily, our bodies produce antioxidants which neutralise the free radicals, but an individual with the SECISBP2 variant lacking such defence, was markedly oversensitive to ultraviolet light.

The function of many selenoproteins is unknown, but the researchers hope that this discovery will help identify potential problems in patients in the future, perhaps via the unusual combination of abnormal thyroid function and other disorders

Professor Krishna Chatterjee, who led the research, says the findings may point to new ways to treat the disorder.

"Trials of selenium supplementation in patients with selenoprotein deficiency have not been beneficial," he explains. "However, we have shown that these patients have elevated levels of free radicals and so treating them with antioxidants may prove to be more effective."

Professor Chatterjee also believes that studying the patients affected by selenoprotein deficiency may provide clues to the short- and longer-term consequences of having raised levels of free radicals.

"It has been suggested that excess can accelerate ageing or increase cancer risk. We hope that studying these patients will help us understand whether or not this is the case and how effective antioxidant therapies are at limiting free radical damage."

The research was supported by the Wellcome Trust, the National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre, the Medical Research Council and the Campaign.

Explore further: Muscular dystrophy: Repair the muscles, not the genetic defect

More information: Schoenmakers E et al. Mutations in the selenocysteine insertion sequence - binding protein 2 gene lead to a multisystem selenoprotein deficiency disorder in humans. J Clin Invest 15 Nov 2010.

add to favorites email to friend print save as pdf

Related Stories

Supplements are not nutritious

Apr 04, 2008

Selenium supplementation, for example in mineral tablets, might not be that beneficial for the majority of people according to researchers writing in the open access journal Genome Biology. Although this trace element is ...

Selenium may slow march of AIDS

Nov 28, 2008

Increasing the production of naturally occurring proteins that contain selenium in human blood cells slows down multiplication of the AIDS virus, according to biochemists.

Antioxidant to retard wrinkles discovered

Aug 30, 2007

A new method for fighting skin wrinkles has been developed at the Hebrew University Faculty of Agriculture, Food and Environmental Quality Sciences.

Antioxidants are unlikely to prevent aging, study suggests

Dec 01, 2008

Diets and beauty products which claim to have anti-oxidant properties are unlikely to prevent ageing, according to research funded by the Wellcome Trust. Researchers at the Institute of Healthy Ageing at UCL (University College ...

Recommended for you

Dendritic cells affect onset and progress of psoriasis

Sep 12, 2014

Different types of dendritic cells in human skin have assorted functions in the early and more advanced stages of psoriasis report researchers in the journal EMBO Molecular Medicine. The scientists suggest that new strate ...

Approach to deadly sepsis infections continues to vary

Sep 12, 2014

Treatment practices for patients hospitalised with the potentially fatal infection known as "sepsis" will continue to vary because of individual differences between hospitals and countries, according to University of Adelaide ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

lengould100
5 / 5 (1) Nov 16, 2010
It seems there's an awful lot of quite random studying of various elements as nutrients or poisons, without much overall knowledge. On week we hear that a suplement may provide vital service, the next that it may damage heart valves (for example).

Seems to me people should simply eat a balanced diet in moderation, and wait for science to figure out all the nuances of nutrients.