The Thalassemia And Related Disorders Biology Essay

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The subject area that I interested in is blood disorder related to defective haemoglobin, either too few globin chain synthesised or incorrectly functioning globin. Sickle-cell disease, anemia and thalassemia are all caused by faulty haemoglobin. Among these three diseases, I interested to make a research about thalassemia to get an overall overview on what exactly thalassemia is. It is also important to us to be knowledgeable on thalassemia in order to prevent this disease from more spread out in our community. In general, thalassemia is a hereditary blood disorder which caused by abnormal form of haemoglobin where the there is reduced number of normal haemoglobin due to lack or no synthesis of globin chains in the haemoglobin.(1)

Thalassemia is a blood disorder which caused by abnormal form of haemoglobin. It is a hereditary disease which passed down through families. Generally, alpha and beta protein in the haemoglobin cannot be produced by their cells. Therefore they have insufficient normal haemoglobin in red blood cells to transport oxygen throughout the body. There are four types of common thalassemia which are alpha thalassemia, beta thalassemia, delta-beta thalassemia and haemoglobin E-beta thalassemia. Alpha thalassemia occurs due to deletion one or more of the alphaglobin chain loci whereas beta thalassemia is caused by total or partial lack of beta-chain production. The symptoms of this disease include paleness, poor development and abdominal enlargement in infant. Meanwhile in children and adult, long bones become thinner and the marrow cavities dilate. Their maxillary sinuses enlarged, ears, nose and throat are infected as well as testicular and ovarian failed to function. There is no definite cure for this disease; only supportive management of anaemia is possible such as blood transfusion, iron chelation to remove excess iron after blood transfusions, splenectomy to treat hypersplenism, bone marrow transplantation and somatic gene therapy. However, despite all the treatment mentioned above, prevention is the best way to avoid thalassemia. The possible ways to prevent thalassemia are by avoiding intermarriages and through prenatal diagnosis programs.(1)

Second article "Alpha and Beta Thalassemia"

This article illustrates specifically about the occurrence of alpha and beta thalassemias. Generally, alpha and beta thalassemia are caused by abridged or missing alpha and beta globin chains in the haemoglobin respectively. Therefore, in alpha thalassemics, they will have excess synthesis of beta globin chains and in beta thalassemic, they will have an excess number of alpha globin chains. The genes that are responsible for this hereditary disease are two genes of Chromosomes 16 for alpha thalassemia and one gene on each Chromosomes 11 for beta thalassemia.To be particular, alpha and beta thalassemias can be divided into four main categories which are thalassemia minor, intermedia and major and silent carriers. Alpha thalassemia minor is caused by absence of two genes that control the alpha globin and it is asymptomatic, hence no treatment is needed. Meanwhile, alpha thalassemia intermedia is caused by the missing of three genes which lead to haemolytic anemia, ineffective erythropoiesis, splenomegaly and four gene deletions accounts for alpha thalassemia major. Alpha thalassemia major is the severe one and can lead to death. In comparison with alpha thalassemia, beta thalassemia minor is caused by absence for only one gene but resulted in mild anemia. Deletions of two beta globin chains can cause beta thalassemia intermedia and major. However, beta thalassemia major is the most severe form of beta thalassemia because there is less or no beta globin synthesis in the haemoglobin. Patients with beta thalassemia major require blood transfusion throughout their life and there is a probability that bone marrow transplantation can cure children with this category of thalassemia. Patients who receive blood transfusions should undergo iron chelation therapy to remove excess iron or else they will encounter cardiac complications due to excessive iron in their blood.(2)

Third article "Globin Chain Synthesis in Alpha Thalassemia Syndromes"

The article discusses about alpha thalassemia in particular. The four types of alpha thalassemias discussed are thalassemia trait, hydropsfetalis, haemoglobin H disease (HbH) and "silent carrier". Patients who suffer from thalassemia trait may have microcytosis (enlargement of red blood cells with nearly constant haemoglobin concentration) and no or little anemia. Hydropsfetalis can cause early death of unborn baby or death during birth, meanwhile HbH disease account for hemolytic hypochromic anemia. The "silent carrier" is here defined as the hematologically normal parent of an individual with hemoglobin H disease. The author presents an occurrence evidence of three categories of alpha thalassemia ie thalassemia trait, haemoglobin H disease and "silent carrier" by studying the rates of production of alpha and beta chains in haemoglobin of normal individual and patients with those three types of alpha thalassemia. This experiment is carried out by measuring the integration rate of leucine-1"C into alpha and beta chains in the haemoglobin of sample blood of the subjects. The results of this study are: in normal individual, the alpha/beta ratio is found to be 1.02±0.07, 0.77±0.05 for alpha thalassemia trait, 0.41±0.11 in patients with HbH disease. Meanwhile, in silent carriers, the measurement is 0.88. From the results, it can be concluded that the synthesis of alpha globin chains is lesser than the production of beta goblin chains in alpha thalassemia patients.(3)


Article 1

Article 2

Article 3

Area of study

This article discusses about thalassemia in general. It is an overview to show the basic ideas on what actually thalassemias are, what are the types of thalassemias, their symptoms, treatments and prevention method to avoid getting thalassemia.

This article discusses about two common types of thalassemia which are alpha and beta thalassemia. It also provides some pathopsyciological information about these two types of thalassemia. The author also provides the treatments available for the thalassemic patients and managements of specifics conditions that are caused by thalassemia disease such as

This article focused only on the alpha thalassemia disorder. An investigation is carried out to compare the number of alpha globin chains production in normal individual, silent carriers, alpha thalassemia trait and haemoglobin H disease in relative to the beta globin chain production in their blood samples.

Types of thalassemia discussed

The article discussed about four types of thalassemia which are alpha thalassemia, beta thalassemia, delta-beta thalassemia and haemoglobin E thalassemia.

The article focused on only alpha and beta thalassemia. Alpha and beta thalassemia are further divided into three main categories which are alpha and thalassemia minor, intermedia and major. There is also "silent carriers" in the alpha thalassemia.

The article described about four categories of alpha thalassemia. There are alpha thalassemia trait, hydropsfetalis, haemoglobin H disease and "silent carriers". However, the experiment on alpha globin chains is only carried out for alpha thalassemia trait, haemoglobin H disease and "silent carriers".

Clinical features

All three articles discussed about the clinical features of thalassemia.

Management of disease

Both articles provide the available treatments to treat this blood disorder. The required treatments are blood transfusions, iron chelation therapy to remove excess iron after blood transfusions, bone marrow transplantations, somatic gene therapy (endocrinopathies) and splenectomy to treat hypersplenism.

The author does not discuss about treatment of thalassemia in this article.

There are other therapeutic measures stated by the author in order to manage the disease are, prevention of hemosiderosis

The author also provides other measures such as preconception genetic counselling during pregnancy, serum ferritin to predict cardiac complications and supply of folic acid for patients with folic acid deficiency.

Case study

Both articles do not include an investigation study as an evidence of occurrence of thalassemia.

One experiment is being carried out to investigate the rate of production of alpha globin chain in patient's haemoglobins to provide an evidence that individual with alpha thalassemia will have reduced alpha globin synthesis. The severity of the reduction of alpha globin is dependent on type of alpha thalassemia. For example, haemoglobin H disease has lesser alpha globin than alpha thalassemia trait; therefore, HbH is more severe than alpha thalassemia trait.


The objective of this research is to get a general idea of what exactly the thalassemia is. Therefore in my opinion, Article 2 is the most appropriate source to achieve this purpose. Article 1 and Article 2 both give general overview on thalassemia in terms of classifications of thalassemia, how it happens, symptoms, therapeutic measures to treat thalassemia as well as prevention steps. Nonetheless, Article 2 provides a wider range of information as it includes the pathophysiological information on the abnormal haemoglobin of this disease and diagnosis of patients with this disease. On the other hand, Article 3 is not a very suitable source to know about thalassemia in general because it specifically focused on only alpha thalassemia. However, Article 3 is the most scientifically reliable source among those three articles because it presents experimental evidence on the factor that lead to alpha thalassemia (ie reduced alpha globin synthesis). Apart from that, the organisation of information in Article no.2 is clear and well-structured. In addition, the information is also illustrated in form of tables and diagrams which help me to understand the topic better. In all three articles, there are no contradictions found.