What is sickle cell disease?

• Sickle cell disease is a lifelong condition caused by a faulty gene that affects how red blood cells develop
• SCD mainly affects people of African, Caribbean, Middle Eastern, eastern Mediterranean and Asian origin. It is the fastest-growing genetic disease in the UK, but most cases are in sub-Saharan Africa
• According to the US Centers for Disease Control, sickle cell trait is common among people who live in areas where malaria is endemic
• People with sickle cell are often at an increased risk of contracting serious infections or they could become anaemic, which is when red blood cells cannot carry enough oxygen around the body. This can cause tiredness and shortness of breath
• Some patients have regular blood transfusions – usually every three to four weeks – as a form of treatment for the condition.
• A year ago, a French teenager’s sickle cell disease was reversed using gene therapy – a rare and expensive treatment.
It is “imperative to use this new classification for improving our clinical care”, Dr Rotimi says, in Africa and around the world.
But Frederick B. Piel of Imperial College London has told the New York Times that he wants to see bigger studies to see if they come to the same conclusions.
For decades scientists have wondered whether the mutation happened just once, or whether it happened at different times in different places.
Sickle cells were first found in the US in people of African origin, but they are also common in people from the eastern Mediterranean (particularly Greece), the Middle East and parts of Asia.
Up until now, he says, “we’ve been labelling these various types using ethnolinguistic groups which really does not provide any clinical insight – those are just where the patient was first noted,” Dr Rotimi says.
Perhaps, researchers thought, there wasn’t just one “once upon a time”. Instead several children developed the advantage against malaria separately. So it happened once upon a time in Senegal, and once upon a time in Cameroon, and in Benin, and in the Central African Republic.
But Dr Shriner and Dr Rotimi found that the people they traced had very similar genetic mutations, with those in Kenya, Uganda, South Africa and the Central African Republic being so similar that they would fit a pattern of having been distributed by migrations of the Bantu people.
The Bantu, from West Africa, moved eastward and southward about 2,500 years ago.
So is Dr Rotimi certain of what his study has found?
At that question, he laughs out loud: “As a scientist it’s always a bad idea to say something is final. I never really take the position that this is the final answer.”
But, he says: “The information that we have now seems to make it quite clear that the multiple origin is not supported.”
And from a scientist, perhaps that is as close to “once upon a time” as we are going to get.
Bigger studies may or may not come up with the same results, but for now, the image endures of one lucky child with a very mixed global legacy.

Source: BBCNews.com

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