An Overview Of Sickle Cell Anaemia Biology Essay

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The purpose of the essay is that we need to explain the genetic disorder in detail and introduces the genetic disorder, explains the genetic disorder and evaluates information to make a recommendation in Jonathon's situation.

Red blood cells (RBCs) contain an iron-rich protein called "Haemoglobin". Haemoglobin is the main ingredient in red blood cells. Sickle cell anaemia is a blood syndrome that affects haemoglobin in the RBCs. It needed to bring oxygen from the lungs to the hold body. Normal red blood cells have haemoglobin A. Haemoglobin A keep red blood cells soft, flexible and round - look like a donut shape. Also, it allows them to flow easily through small blood vessels. On the other hand, people with sickle cell disease have haemoglobin S in their red blood cells. Under unsure conditions, haemoglobin S causes blood cells to become hard and form a sickle or half-moon shape or banana shape. Un-normal red blood cells are also less flexible than normal red blood cells. Sickle shaped haemoglobin can block small blood vessels causing a lot of problems such as, pain, organ damage, or stroke.

Looking at the figure A, it shows that normal red blood cells (RBCs) flowing freely in a blood vessel. The inset image shows a cross-section of a normal red blood cell with normal hemoglobin.

In figure B, we can see the abnormal sickled red blood cells blocking blood flow in a blood vessel. The inset image shows a cross-section of a sickle cell with abnormal SS hemoglobin forming abnormal strands.A professor of medicine called James B. Herrick (1861-1954), whose intern Ernest Edward Irons (1877-1959) found "peculiar elongated and sickle-shaped" cells in the blood of Walter Clement Noel, a 20 years old university student in 1904 (Chicago ,USA) . He was suffering from this disease (sickle cell anaemia) from then till the rest of his life.

Nowadays, we call this disease with lots kind of name like HbS disease or Sickling disorder due to homolog S or Haemoglobin SS disease and more.

Sickle cell disease largely affects people in Mediterranean, African, Middle Eastern, and Asian Indian ancestry. Worldwide, 1 in every 250,000 babies is born with sickle cell disease. One in 12 African American has sickle cell trait. One in every 1000-1400 Latino births are affected. Around 1 of 500 children born in the US will have sickle cells. Also, in the UK, 1 baby in every 2000 is born with this condition as well.


Sickle cell anaemia occurs because an abnormal form of haemoglobin SS disease (HbS) is produced in the blood vessels. This disease is likely to clump together, making RBCs sticky, stiff, fragile and causing them to form into a curved, sickle shape like half-moon shape or banana shape.

Normal red blood cell (RBCs) containing HbS that it can go back and forth between being shaped usually and being sickle cell shaped until all the cells finally become sickle shaped permanently. So instead of moving through the bloodstream without difficulty, these sickle cells can block blood vessels because they are not flexible and take away the body's tissues and organs of the O2 that they need to stay healthy.

Not like normal RBCs that last about 3 to 4 months in the blood vessels. Sickle cells eventually break down after about 12 to 20 days in a roll, which naturally causes anaemia. Anaemia is what occurs when the body's number of RBCs (or amount of haemoglobin) falls underneath normal (males is between 4.7-6.1 million red blood cells per micro liter and for females the range is around 4.2-5.4 million cells per micro liter of blood). People who are anaemic often feel weak and feel tire more easily.

Normal Red Blood Cell

Sickle Cell Red Blood Cell

DNA sequence



Complementary RNA sequence



Amino acid sequence

leu --- thr --- pro --- glu

leu --- thr --- pro --- val

Phenotype of Red Blood Cell

Looking at the symptoms and signs of the disease, people with sickling disorder due to homolog S may develop Jaundice - known as icterus, is a term used to describe a yellowish tinged to the skin and the white part of the eye that is caused by hyperbilirubinemia (an excess of bilirubin in the blood).

People with sickle cell anaemia also may have short period or long period of severe pain in their chest, arms, legs, stomach or other parts of their body depending on the effect of the disease. The periods of pain are regularly brought up pain crises which vary in their severity, how often they happen and how long they last for. Though one person may have only one sickle cell pain crisis a year or others may have them more often. The pain can be brief or last for many hours, days or sometime it lasts for a weeks. Occasionally, pain can be painful enough to involve treatment in the hospital. This is caused by sickle cells blocking the blood that flow through the small blood vessels in the areas. They normally feel tired and have trouble fighting with the infections are also common among those people with sickle cell anaemia. The reasons why people finding are hard to fight with the infection because the disease can damage the spleen, an organ that helps fight infections. Also, sickle-shaped red blood cells get stuck in the narrow blood vessels and they block the flow of blood and the results in a vaso-occlusive crisis. The results of the disease are: hand and foot syndrome; pain that occurs unpredictably in anybody organ or joint; eye problems; leg ulcers; fatigue, paleness, shortness of breath; cholelithiasus and cholecystitis. The child with Haemoglobin SS disease may grow more slowly and reach puberty later than other teenagers the same age as them.

First, hand and foot syndrome is a common in people with sickle cell disease. The blockage of small blood vessels causes painful swelling of the hand and feet, due to the death of the bone area. This is maybe the first sign of sickle cell disease. Next, the other affection is pain that occurs randomly in anybody organ or joint (arms, legs, chest and abdomen). A long-suffering may experience pain wherever sickled blood cells block oxygen flow to tissues. Certain patients have hurting period time less than once a year, and some have lots, like 15 or more than that in a year. For especially on going pain, the long suffering may be hospitalized and treated with painkillers and intravenous fluids. Pain is the principal symptom of sickle cell anaemia in both children and adults. Third, eye problems are retinas can get worse when it doesn't get enough nourishment from circulating the red blood cells. It's serious enough to cause blindness. Few others are leg ulcers, shortness of breath; Cholelithiasus (gallstones) and cholecystitis. People with sickle cell anaemia have higher risk of certain infections and stroke as well as a condition called acute chest syndrome, that can caused by inflammation, infection, or blockages of blood vessels in the lungs by the sickle cells.

Sickle cell anaemia is not contagious, so that we cannot catch the disease from anyone else or pass it to another people like a cold or virus or any infection. People who have sickle cell anaemia have inherited two sickle cell genes, one from each parent (the mother and the father). The child that has inherited the SCGs from only one parent will not develop the disease. However they will have sickle cell trait (call carrier). People who have sickle cell trait (SCT) don't have sickle cell anaemia and normally don't have the signs of the syndrome, but then again they can pass the disease genes on to their children (their next generation). Looking at the picture beside, we can see that there is one unaffected "carrier" father (1 normal gene and 1 sickle cell gene) and one unaffected "carrier" mother (1 normal gene and 1 sickle cell gene). When they have children, the precents or chance of the child who doesn't have the disease is 1 in 4 chances (25%). The precents or chance of the children who have sickle cell trait (carrier) are 2 in 4 chances (50%). Last, the precents or chance of the child who has the disease is 1 in 4 chances (25%).

In the second picture (right hand side) there is one unaffected "carrier" father/mother (1 normal gene and 1 sickle cell gene) and there is 1 unaffected mother/father (2 normal genes). When they have children, the precents or chance of the child who don't have the disease is 2 in 4 chances (50%). On the other hand, the precents or chance of the child who have cell train are 2 in 4 chances (50%).

However, people with sickle cell trait don't have the disease so that they may never find out that they carry the sickle cells gene. That's why the doctor recommended that people who are not sure of their sickle cell status, they should ask their doctors about testing. So to identify sickle cell anaemia, the doctor will use a special blood test called "a haemoglobin electrophoresis" to look for sickle haemoglobin SS disease in a person's blood. About the haemoglobin electrophoresis blood test, it requires a few millilitres of blood from a vein. The test itself uses a method of determining the type and size of haemoglobin molecules in the blood. It is observing the rates of transit of these negatively-charged proteins in an electric field medium. So Jonathon Jackson of course should take this blood test because of his own health and benefit.

Although most young people with sickle cell anaemia don't die but the chance for someone to be ill enough to die from the disease is posible. However, the doctors can provide treatments that help stop the problems from the disease. Special treatment depends on the type of anaemia that the person gets. Normally, sickle cell anaemia will require lifelong folic acid and penicillin twice daily to avoid and stop the infection. Treatment currently under investigation includes: hydroxyurea; bone marrow transplant; Gene therapy; dietary cyanate; analgesics; folic acid and penicillin

Hydroxyurea is an anticancer drug reduces the frequency of crises and avoids the need for transfusion. It is thought to work by boosting production of fetal haemoglobin, a protein normally made only by foetuses and newborns. The drug is still being monitored for side effect. Second, bone marrow transplant - this can help, but chances of finding a match are pretty low. Third, gene therapy is one approach is to engineer haemopoietic stem cells and implant them into the marrow; another is to turn off the defective gene while switching on the gene for fetal haemoglobin. Next, dietary cyanate- in the test site, cyanate and thiocyanate permanently inhibit sickling of RBCs drawn from Sickling disorder due to homolog S patients. The patient for a lifetime, as each new RBCs created must be stopped from sickling at the time of creation. Cyanate is expelled via the area of a patient every cycle of treatment. Other treatment is Analgesics, painful crises are treated symptomatically with oral and intravenous hydration and a plan of painkillers increasingly stronger: pain controlling requires in the first time management of paracetamol at regular pauses until the crisis has settled. With more severe crises, a minor group of patients manages on NSAIDs (like diclofenac or naproxen). Patients require opioids and only when the patients cannot control the painful crisis require inpatient management for blood at the same time. Diphenhydramine is an effective agent that is frequently recommended by doctors to help control any itching associated with the use of opioids. Finally, folic acid and penicillin. Under closer observation by the paediatrician and the management by a haematologist they'll try to stay healthy. This patient will take a 1 mg dose of folic acid a day for the rest of this person life. From birth to four or five years old, they will have to take penicillin every day and they have to benefit from routine vaccination for H. influenza, S. pneumonia, and Neisseria meningitides due to the immature immune system. Another treatment being investigated is Senicapoc.

Some pain can be managed at home with pain medicines, rest, and extra fluids. But if the pain is especially strong, so they may need to go to the hospital to have a better treatment.

Many people with sickle cell anaemia occasionally need to get transfusions of healthy red blood cells to help carry the oxygen to their bodies more effectively. Some situation may need to transfusions regularly.

Scientists are researching ways to help people with sickle cell anaemia. There are quite a lot of new treatments like the drug hydroxyurea that can helped reduce the pain crises and episodes of acute chest disease for people with sickle cell. Bone marrow transplant, a complex and risky process, is the only cure for Haemoglobin SS disease.

Scientists are studying gene therapy as a treatment for the disease. Oneday, we are hoping that they may be able to stop the disease by exchanging or replacing the un-normal gene that causes it.

With the right protections, people who have Haemoglobin SS disease could do most of the stuff that other normal people can do. To stay as healthy as possible, they should eat a balanced, healthy diet and of course exercise is important for staying healthy too. Drinking plenty of fluids to avoid dehydration and get plenty of rest because they need it. It is very important that they must avoid alcohol, drugs, and smoking, which can make the sickle cell disease worse. Next, prevent serious infections by contact their doctor as soon as possible (when the illness symptoms start). Be sure to get any injections that the doctor recommends, and always call the doctor if they have a high fever because it is dangerous. They also need to avoid places with low oxygen. Finally, take medications, including folic acid supplements, as prescribed.


Based on Jonathan's genetic disorder (Sickle Cell Anaemia) and his situation, evaluate if genetic testing is a fair process when signs and symptoms of the genetic disorder may not be present. I strongly disagree that the company has dismissed Jonathan from his job where he had worked faithfully for more than eight years. This is not right! His disease is not contagious so that he cannot give it to someone else in the company. The company should help and support him, not ignore and fine him because he has the disease. The disease that he is caring is not his choice and is not his fault. He doesn't deserve to have that.