What is sickle cell anaemia?

Five seemingly unconnected Black and ethnic minority Londoners discover they have superpowers in the hit Netflix series "Supacell". The link between them? They all suffer from sickle cell anaemia, a condition that disproportionately affects people of colour.

Beyond "subtly interspersing real-life issues that affect Black Britons" into the plot, the inclusion of sickle cell anaemia is its "biggest real-life undercurrent", wrote Lanre Bakare in The Guardian . The show began airing in June, a month after the UK's National Institute for Health and Care Excellence (Nice) approved a new drug that may alleviate the symptoms of the illness for the thousands of people who suffer from it.

What is sickle cell anaemia?

Sickle cell anaemia is a genetic condition in which the shape of blood cells changes into crescents reminiscent of a sickle, a mutation which can cause episodes of severe pain and other symptoms, and shorten life expectancy.

In the UK, approximately 17,500 people live with sickle cell disease. Only one in five people know about the disease, according to Rapman, the creator of "Supacell", who is also known as Andrew Onwubolu. "It's crazy how unknown it is, especially for a disease that affects so many people," he told The Guardian.

How is it different from sickle cell disease?

Sickle cell disease refers to a set of related genetic conditions that affect red blood cells. Sickle cell anaemia is the most common and the most serious, and occurs in people who have inherited the gene from both parents, according to the NHS . Sickle cell disease predominantly affects people with an African or Caribbean heritage, as well as a smaller number of people with South Asian, Latin American or Middle Eastern ancestry.

What are the symptoms?

The main symptom of sickle cell disease, said the NHS, is painful episodes called "sickle cell crises" that can be "very severe" and last for days or weeks. These can be triggered by exposure to cold, sudden temperature changes or dehydration.

Those living with sickle cell disease are prone to anaemia episodes because in the misshapen red blood cells cannot carry enough oxygen around the body, leading to shortness of breath and tiredness. The deformed blood cells can also cause blockages in blood vessels, putting patients at risk of strokes and coma. Sickle cell disease is also associated with a higher susceptibility to certain types of infection. Sickle cell anaemia is a life-limiting condition that can shorten life expectancy by 20 to 30 years at its most severe, although average life expectancy with the disease has increased in recent years.

Why does it mostly affect Black and ethnic minority people?

This genetic variant is common among people from specific ethnic groups because the sickle shape of the red blood cell is "inhospitable to the parasite that causes malaria", said red blood cell researcher Johan Flygare on The Conversation . Technically, therefore, sickle cell disease protects individuals from malaria. But the sickle-shaped cells break down very easily as a result, and this leads to many of the symptoms.

What is the treatment?

Sickle cell anaemia sufferers need frequent blood transfusions. These offer quick relief to improve oxygen levels and reduce stroke risk, but they also cause iron to build up in vital organs like the heart and liver. There is also the potential for life-threatening immune reactions, such as "transfusion-related acute lung injuries", said Flygare.

Treatment options also include hydroxyurea, a relatively cheap drug that induces the production of a foetal version of the haemoglobin gene. This, in turn, leads to the formation of red blood cells and alleviates symptoms – but it also reduces the white blood cell count, which can weaken the immune system.

A new drug called Voxelotor which alleviates the symptoms of sickle cell disease has been described as "life-changing". It works by helping haemoglobin hold on to more oxygen and prevent them from becoming misshapen, said Sky News . Although it was initially rejected for widespread NHS use, Nice approved the drug in May for treating sickle cell anaemia in people aged 12 and older, with around 4,000 patients set to benefit.