WHAT IS SICKLE CELL DISEASE?
Genetics is the branch of biology that deals with the continuity of features from one generation to the next. It answers questions like why do children in a family resemble one another but are not alike, why do the offspring resemble their parents partly, etc. The answers lie in zygotes. There are two main categories of genetics branch; Heredity and Variation. Heredity is the transmission of characters from parents to offspring while variation is the influence due to which no two living beings look alike.
The offspring not only inherit traits from their parents like the same eye colour, hair colour, blood group, etc. they also inherit certain diseases like haemophilia, colour blindness and sickle cell disease from the parents. It is not always necessary that offspring resemble their parents. The resemblances of offspring depend on the inherited genes but in many instances the inherited genes are unable to express themselves. Variations can arise due to changes in the number of chromosomes, the constitution of genes, etc. These kinds of changes are considered mutations. Due to mutation, there occurs a mistake or misprint in cell division which results in the alteration of DNA sequences.
Mainly there are three types of mutations; numerical, structural and genetic. Numerical mutation occurs due to the change in a number of chromosomes. Every human being carries 23 pairs i.e., 46 chromosomes, in numerical mutation there occurs a change in either number of chromosomes or set of chromosomes. The loss or gain of chromosomes can result in abnormalities.
Every species is characterized by the presence of a specific number of chromosomes at a specific location. If changes occur in the number and arrangement of genes, it is called a structural mutation. It includes deletion, duplication, inversion and translocation of a gene in a chromosome. Due to this kind of mutation, diseases like cancer, cri-du-chat disease, etc. occur in humans.
Any mutation induced by a change in the constitution of a gene is called a genetic mutation. DNA is the genetic material; mutation causes alteration in the information of DNA. A mutated gene is harmful to the individual. Any gene can undergo mutations; which can be spontaneous or induced. An example of genetic mutation is sickle cell anaemia, where haemoglobin becomes defective and the red blood cells (RBC) take a sickle shape.
ABOUT SICKLE CELL ANAEMIA – it is a hereditary disease. It is characterized by the presence of sickle-shaped RBCs under low oxygen pressure. Sickle cell anaemia is due to presence of defective haemoglobin called Hb S. The defect is caused by the substitution of Glutamic acid with Valine at the sixth position of the beta chain of the haemoglobin molecule.
Red blood cells in normal conditions are round and flexible, that’s the reason why they are able to move through blood vessels. When a person suffers from sickle cell disease, some red blood cells become rigid, sticky and sickle shaped. This affects the flow of blood making it slow and creating blockage.
SYMPTOMS OF SICKLE CELL ANAEMIA – this hereditary disease shows its sign in a human when they are merely an infant 6 months. The symptoms are as follows –
· Anaemic condition- the normal shelf life of a healthy red blood cell is of 120 days. Naturally, the red blood cells are replaced by new ones in these mentioned days. In anaemic condition the sickle shaped red blood cells live only for 11- 21 days after which they break apart easily and die. This results in shortage of red blood cells and the body does not receive enough oxygen leading to tiredness and fatigue.
· Pain in many areas of the body – as the red blood cells become sickle cells, their passage from tiny blood vessels causes a lot of pain in the chest, abdomen and joints. The pain episodes can occur once a year or frequently in different people. The pain can get severe in many conditions resulting in joint damage, ulcers, etc.
· Physical issues – the red blood cells are responsible for carrying oxygen to each part of the body. If any kind of issue occurs in the RBC’ it affects the entire system. The sickle cell anaemia causes blockage in circulation of the RBC’ which in turn leads to swollen hands and feet. The RBC transport nutrients for the growth of a human body. The shortage in nutrients leads to slow growth in infants and delayed puberty. The vessels supplying the eyes can also be infected by the sickle cells which block the area around the retina leading to vision problems.
· Vulnerable to infections – a hereditary disease can lead to many malfunctions in the human body. In sickle cell disease, the spleen is directly affected. The spleen plays an important role in fighting the germs that have invaded the blood, it controls the level of white blood cells, red blood cells and platelets. The spleen filters the blood and removes the damaged cells. In the sickle cell condition, the spleen is damaged which increases the vulnerability of the person getting infected.
URGENCY TO SEE A DOCTOR – certain disease brings complications to the human body. If the above symptoms are observed in a person, they should immediately consult a doctor, or genetic counsellor for possible treatments, preventive measures, etc. Here are a few signs and complications which come along the sickle cell disease –
· Stroke like condition – when it becomes difficult for red blood cells to pass through a vessel, pain is experienced in certain areas of the body. Arms and feet experience weakness, unconsciousness, and blockage in blood flow to the brain area can lead to strokes. If such a condition arises, one should see a doctor and take an emergency medical treatment.
· Organ damage – the sickle cell disease damages the spleen, a crucial organ to fight blood infections. The disease hampers the flow of healthy blood cells to other organs, depriving oxygen. This condition increases the risk of organ failure of kidneys, liver, etc.
· Complications in pregnancy – sickle cell disease comes along with high blood pressure and blood clots in a pregnant woman. Due to which chances of miscarriage, premature birth and low weight of newborn occurs.
WAY FORWARD – the hereditary disease does not have a complete cure. Getting a counselling session from a genetic counsellor can help get remedies and medicine. Treatments can relieve pain and prevent major complications.
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