Introduction

Sickle cell anaemia is a serious inherited blood disorder where the red blood cells, which carries oxygen around the body, develop abnormally. It affects the red blood cells, causing episodes of sickling, which produces episodes of pain and other serious symptoms. 

Normal red blood cells are flexible and round-shaped, but in sickle cell anaemia they can become rigid and shaped like a crescent (or sickle). The sickle-shaped cells contain defective haemoglobin, which is the iron-rich protein that enables red blood cells to carry oxygen from your lungs to the rest of the body. 

 
The abnormal cells are also unable to move around as easily as normal shaped cells and can block blood vessels, resulting in tissue and organ damage and episodes of severe pain. Such episodes are known as a sickle cell crisis or a vaso-occlusive crisis. They can last from a few minutes to several months, although on average most last five to seven days. The abnormal blood cells also have a shorter lifespan and aren't replaced as quickly as normal blood cells. This leads to a shortage of red blood cells, known as anaemia. Symptoms of anaemia include lethargy (a lack of energy), tiredness and breathlessness, particularly after exercise. 

 
What causes sickle cell anaemia? 
 

Sickle cell anaemia is caused by a mutation (an abnormal change) in the gene that instructs the body to produce haemoglobin. The sickle cell gene is inherited (passed on between family members). To get sickle cell anaemia you have to inherit the defective gene from both parents. 
 
If you only inherit the gene from one parent, you have what's known as the sickle cell trait. It's likely that your blood will contain some sickle cells, but you'll be able to produce normal haemoglobin and won't usually experience symptoms. However, you'll be a carrier of sickle cell anaemia and may pass the abnormal gene on to your children. Those who inherit the gene from both parents do not have this protection. In addition, they suffer from severe effects of SCD and many die before they reach reproductive age.
                                        

If two people with the sickle cell trait have a child, there's a one in four chance that the child will be born with sickle cell anaemia. 

 
Nigeria:
 

Nigeria has an estimated population of 178 million with an annual growth rate of 3.2%. About 25% of adults have the sickle cell trait, AS. This suggests that there is a potential growth with the number of babies who will be born with sickle cell disease. 

The Sickle Cell Foundation Nigeria records that around 150,000 babies are born with sickle cell disease each year.
 

According to the WHO, the geographic distribution of the sickle-cell trait is very similar to that of malaria. The sickle cell trait has a partial protective effect against malaria, and this may explain why it has been maintained at such high prevalence levels in tropical Africa.  
 

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