Sickle cell disease is the most common inherited blood disease in the world, Nigeria is home to the largest number of persons living with sickle cell disease (affects 2 out of every 100 children). Like me, you may have someone in your family living with it. Hence, knowing your blood genotype is essential, and a simple test can solve this need.
From the pool of haemoglobin variants that exist, parents donate one each to give any of the different combinations, common among which are HbAA, HbAS, HbAC, HbSS, HbSC, and HbS-beta thalassemia.
Sickle cell trait – AS and AC
You could inherit the HbAS or HbAC genotype when both parents have HbAS/AC genotypes or when one parent has HbAA and the other has HbAS/AC or HbSS/SC. People with these genotypes are called ‘carriers’ and are healthy. In fact, the single abnormal gene protects them from severe malaria which is a reason it is so rampant here where mosquitoes are also citizens.
Sickle cell disease – SS, SC, Sbeta+thalassemia
A child is likely to inherit either of these genotypes when both parents are HbAS or one has HbAS and the other has HbAC or HbAbeta+thalassemia, which explains the popular counsel for such couples to avoid making babies together. The chance of this occurring in each child is 1 in 4. This does not mean that if they have four children, only one of them would inherit the SS genotype. Some families go on to have two, three or more children with the genotype while some have none. It’s a risk.
The condition is largely characterized by low blood level (as the abnormal red cells get destroyed faster than the body can replace them), painful episodes/crises, organ damage and in many cases, quite sadly, a shortened life span. Because the abnormal sickle red cells clog up small blood tubes, it causes damage to different organs. A stroke could happen leading to inability to walk and/or do other usual things. The penis could also be affected in males leading to impotence after repeated episodes of priapism. There could be heart failure or liver or kidney problems and the constant risk of severe infections as the spleen which normally serves as a barrier to infection is destroyed.
Current treatments aim at increasing the level of foetal haemoglobin (HbF) in the blood as this type is stable and more oxygen-friendly and therefore reduces the number of crises. The usual advice is to take a lot of fluids, avoid extreme temperatures, avoid stress, and take prophylactic (treatment given in order to prevent an illness) antibiotic and malaria medication. Having complete immunization is also key. Some people living with sickle cell disease (SCD) have a milder form with less frequent crises.
People with the SC genotype have a similar experience except for milder symptoms and rarely have the characteristic outward features of sickle cell disease. Still, it puts them at risk of damage to the spleen (which can be sudden and deadly), the eye, and could affect a bone in the hip; these complications are more common with them. They are also at risk of infections and all the other complications of SCD. Close monitoring is therefore needed.
Children of parents with AS genotype may inherit AA as well as children of parents with the AA genotype. It is not completely advantageous as people with this genotype are more susceptible to severe malaria although they are spared the burden of carefully considering their childbearing partners’ genotype.
Please don’t hesitate to SHARE your experiences (good and bad, joys and trials), and questions in the comment section. Stay tuned for winning with sickle cell disease.