HEALTH: Genetic lifeline for sickle cell anaemia sufferers; A scientific breakthrough could provide hope for sickle cell sufferers. Emma Pomfret explains.
A potential new treatment could offer hope for more than 6,000 British adults and children thought to be affected by a life-threatening condition - sickle cell anaemia.
Scientists have discovered that embryonic stem cells could be used to correct the genetic abnormality causing the inherited condition, which mainly affects people of African descent.
The condition stops red blood cells carrying oxygen to the lungs as efficiently, and can result in severe pain and damaged organs.
Although the symptoms can be treated, the disorder can only currently be cured with a bone marrow transplant from a suitable donor.
The embryonic stem (ES) cells - obtained from genetically-engineered mice carrying human genes with the sickle cell mutation - have the potential to be transplanted back to the body to produce a multiplying supply of healthy and normal blood cells, according to the new research, published in the journal Proceedings of the National Academy of Sciences.
"This approach can be applied to human ES cells to correct the sickle mutation," writes the medical team at the University of California at San Francisco, adding that further research is needed before the therapy can be applied on people.
"This research is wonderful news but this is based on a mouse model and, although we welcome the findings, we hope that there is not a false dawn when the findings are eventually extrapolated on to humans," says Dr Asaah Nko-hkwo, chief executive of the Sickle Cell Society.
"It is a clever thing they have done but it is not yet at that level where we can say that we have reached the Holy Grail and can replicate those findings in humans.
"However, it is very reassuring to see that research is now advancing into a cure for sickle cell anaemia as well as pain management.
"Sickle cell anaemia affects the red blood cells which contain a special protein called haemoglobin, the function of which is to carry oxygen from the lungs to all parts of the body.
"People with sickle cell anaemia have sickle haemoglobin which is different from normal haemoglobin and, because of their shape, sickled red blood cells can't squeeze through small blood vessels as easily as the almost doughnut-shaped normal cells.
"This can lead to these small blood vessels getting blocked which then stops the oxygen from getting through to where it is needed, a process known as sickling crisis."
Everyone has two copies of the gene for haemoglobin, one from their mother and one from their father, explains Nkohkwo.
"If only one of these genes is affected, the person has sickle cell trait which means that they don't have the symptoms of the sickle cell disorders, but they do have to be careful when doing things where there is less oxygen than normal - such as scuba diving, activities at high altitude and under general anaesthetics," he says.
However, if both copies of the haemoglobin gene carry instructions to make sickle haemoglobin then sickle cell anaemia occurs and can cause anaemia and severe pain.
Symptoms are rare before the age of three to six months, but the main symptoms of sickle cell disorders are anaemia, pain or infection, according to Nkohkwo.
"Because blood circulates all over body, a crisis can affect virtually any part of the body, including the brain and the heart.
"Sickle cell disorders can cause pain in the arms, legs, back and stomach as well as swelling of the hands and feet, with stiff painful joints and extreme tiredness.
"Severe attacks of sickle cell anaemia are known as crises - some people get crises quite often and others may have them only once every few years, but most serious acute complications occur during childhood," he warns.
"Over time sickle cell sufferers can experience damage to organs such as liver, kidney, lungs, heart and spleen, and death can be a result."
Although there is no existing cure for sickle cell disorders, doctors and other professionals can help to reduce the frequency and severity of crises and their complications by prompt recognition and treatment.
"People with sickle cell disorders are also at risk of developing severe infections, and are strongly advised to take penicillin twice a day every day as well as folic acid, found in fruit and vegetables, to prevent them becoming run down," advises Nkohkwo.
"Those with sickle cell disorder also need regular medical attention particularly before and after operations, dental extraction and during pregnancy.
"Someone having a crisis will suddenly become unwell or complain of severe abdominal or chest pain, headache, stiffness of the neck or drowsiness and needs urgent hospital treatment."
There are practical steps parents can take to reduce the frequency and severity of sickle cell crises, including making sure the child does not become dehydrated.
For more information visit www.sicklecellsociety.org/inf-ormation/prenatal.htm.
Contact your local sickle cell centre, local obstetrician, hae-matologist or GP.
The Sickle Cell Society is on 020 8961 7795, visit sicklecellsociety.org or email infosicklecellsociety.org
A normal red blood cell and a sickled cell
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|Publication:||The Birmingham Post (England)|
|Date:||Jan 21, 2006|
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