1. What is sickle cell disease? What is the difference between a sickle cell carrier and a patient suffering from SCD? What is the prevalence of SCD?
A sickle cell is a red blood cell that has contorted into a sickle shape. Sickle cell anemia is a group of inherited disorders that cause red blood cells to become sickle instead of normal biconcave shape. In a healthy individual, biconcave red blood cells flow through our narrow vessels to transport oxygen to all parts of our body. However, in a patient who is suffering from SCD red blood cells have abnormal hemoglobin – they take the form of a C-shaped sickle tool. These cells tend to block the vessels and also die early, resulting in excruciating pain and other complications like infection, acute chest syndrome, stroke, and also chronic anaemia.
Sickle cell traits or carriers carry one of the genes for sickle hemoglobin while sickle cell anaemia has both abnormal genes. A second gene is normal in carriers who do not have the disease and will lead a comparatively normal life. When both the parents have traits it can result in the child having sickle cell anaemia.
According to a survey conducted by the Indian Journal of Medical Research (IJMR), the gene is quite widespread in many tribal groups in India with the prevalence of heterozygotes varying around 39% (1-40%). India is also among the three countries that carry nearly 90% of the world’s SCD population (Nigeria, India, and the Democratic Republic of Congo).
2. What are the types of sickle cell disease?
There are four main types of mutations of sickle cell disease that occur through the genes.
There is the Hemoglobin SS (Hb SS) disease i.e.sickle cell anemia, which is the most common type. It occurs when one inherits copies of the haemoglobinS gene from both parents. This is the most severe form of the disease and patients suffering from this type experience the worst symptoms. HbS gene can interact with other abnormal genes and lead to other types of sickle cell disease. The Hemoglobin SC (Hb C) disease is the second most common type and occurs when one inherits the Hb C gene from one parent and the Hb S gene from the other. The anaemia in Hb C is less severe. Haemoglobin SB (beta) thalassemia when one inherits the thalassemia gene from one parent and the Hb S gene from the other.
3. What are the challenges faced by SCD patients?
SCD can lead to several complications. A patient usually has episodes of pain crises, known as vaso-occlusive crises, which vary in intensity and can last from a few days to weeks. These episodes can be triggered by a number of factors like illness, stress, over-activity, and lack of hydration at a high altitude. Recurrent crises can lead to permanent damage to various organs like lungs, liver, kidneys, brain, and bones.
Besides, individuals also face challenges with respect to delayed diagnosis and treatment. In the far-flung areas of the country, a lack of proper medical centers and skilled healthcare professionals make access to screening, diagnosis, and treatment difficult. As a result, more often than not, patients end up losing crucial time before they are put under proper treatment. Timely diagnosis and treatment are critical and have resulted in patients leading better lives.
4. How can SCD be managed?
The main goal of sickle cell disease treatment is to minimize the intensity and frequency of pain episodes and relieve symptoms. This also prevents long-term complications and early deaths. Medications and blood transfusions are prescribed for management. One of the most effective drugs for SCD is hydroxyurea. It has been seen to reduce the frequency of painful crises and in some cases, even the need for hospitalizations.
For certain children or teenagers, stem cell transplants can be undertaken to treat the condition.
In addition, advances are being made to gather deeper insights into the underlying pathophysiology of SCD which enable us to develop targeted therapies to treat disease complications. We now have a new drug called crizanlizumab approved for patients who are not controlled on hydroxyurea.
5. Are there any preventive measures that people can undertake? If yes, what are they?
While there is no known way to prevent the disease, regular screening helps in finding out if one carries the gene mutation. If one does not have sickle cell anemia but people in the family do, they may have inherited one sickle cell gene. This is where they can prevent it from passing down the disease to their children by knowing if their partner has the gene mutation prior to procreating and undertaking pre-natal screening. Additionally, talking to a genetic counselor can help if one may be a carrier. This can help one understand possible treatments, preventive measures, and reproductive options.
6. How can we raise awareness around the issue?
Each year on the 19th of June, the World Sickle Cell Day event is conducted by the United Nations General Assembly to raise awareness of sickle cell disease at a national and international level. In addition, awareness programs need to be conducted and intensified across the country, especially in prevalent states, to make people aware of the condition, the importance of screening and timely diagnosis, and treatment options.
(Dr. Rita Saxena, Associate Professor at Gandhi Medical College)
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