Thalassemia is a genetic blood disorder. People with Thalassemia disease are not able to make enough haemoglobin, which causes severe anaemia. Haemoglobin is found in red blood cells and carries oxygen to all parts of the body. When there is not enough haemoglobin in the red blood cells, oxygen cannot get to all parts of the body. Organs then become starved for oxygen and are unable to function properly.
There are two primary types of Thalassemia disease: Alpha Thalassemia disease and Beta Thalassemia disease.
There are two primary types of Thalassemia disease: Alpha Thalassemia disease and Beta Thalassemia disease. Beta Thalassemia Major (also called Cooley's Anaemia) is a serious illness. Symptoms appear in the first two years of life and include paleness of the skin, poor appetite, irritability, and failure to grow. Proper treatment includes routine blood transfusions and other therapies.
There are two main types of Alpha Thalassemia disease. Alpha Thalassemia Major is a very serious disease in which severe anaemia begins even before birth. Pregnant women carrying affected foetuses are themselves at risk for serious pregnancy and delivery complications. Another type of Alpha Thalassemia is Haemoglobin H disease. There are varying degrees of Haemoglobin H disease.
Thalassemia is a complex group of diseases that are relatively rare in the United States but common in Mediterranean regions and South and South East Asia. Worldwide, there are 350,000 births per year with serious haemoglobinopathies (blood disorders). In the United States, as a consequence of immigration patterns, occurrence of thalassemia disorders is increasing.
The thalassemias are a diverse group of genetic blood diseases characterized by absent or decreased production of normal haemoglobin, resulting in a microcytic anaemia of varying degree. The thalassemias have a distribution concomitant with areas where P. falcipherum malaria is common. The alpha thalassemias are concentrated in South East Asia, Malaysia, and southern China. The beta thalassemias are seen primarily in the areas surrounding Mediterranean Sea, Africa and South East Asia. Due to global migration patterns, there has been an increase in the incidence of thalassemia in North America in the last ten years, primarily due to immigration from South East Asia.
In the normal adult, haemoglobin A, which is composed of two alpha and two beta globins (A2Β2), is the most prevalent, comprising about 95% of all haemoglobin. Two minor haemoglobins also occur: haemoglobin A2, composed of two alpha and two delta globins (α2 δ2) comprises 2-3.5% of haemoglobin, while haemoglobin F, composed of two alpha and two gamma globins (α2 γ2) comprises less than 2% of haemoglobin.
Haemoglobin F, or foetal haemoglobin, is produced by the foetus in utereo and until about 48 weeks after birth. Haemoglobin F has a high oxygen-affinity in order to attract oxygen from maternal blood and deliver it to the foetus. After birth, the production of adult haemoglobin rapidly increases and fetal haemoglobin production drops off.
The genes controlling globin production are on chromosome 16 (alpha globin genes: "α"), and chromosome 11 (beta: "β", gamma: "γ", and delta: "δ" genes). As seen in the diagram, the alpha globin molecule concentration is rather stable in foetal and adult life, because it is needed for both foetal and adult haemoglobin production. The beta globin appears early in foetal life at low levels and begins to rapidly increase after 30 weeks gestational age, reaching a maximum about 30 weeks postnatally. The gamma globin molecule reaches a high level early in foetal life at about 6 weeks and begins to decline about 30 weeks gestational age, reaching a low level about 48 weeks post gestational age. The delta globin appears at a low level at about 30 weeks gestational age and maintains a low profile throughout life.
In the thalassemia patient, a mutation or deletion of the genes that control globin production occurs. This leads to a decreased production of the corresponding globin chains and an abnormal haemoglobin ratio (α:non-α). This abnormal ratio leads to decreased synthesis of haemoglobin and the expression of thalassemia. The globin that is produced in normal amounts winds up in excess and forms red cell aggregates or inclusions. These aggregates become oxidized and damage the cell membrane, leading either to haemolytic, ineffective erythropoiesis, or both. The quantity and properties of these globin chain aggregates determine the characteristics and severity of the thalassemia.
Beta thalassemia :
Beta thalassemia results in an excess of alpha globins, which leads to the formation of alpha globin tetrameters (α4) that accumulate in the erythroblast (immature red blood cell). These aggregates are very insoluble and precipitation interferes with erythropoiesis, cell maturation and cell membrane function, leading to ineffective erythropoiesis and anaemia.
Alpha thalassemia :
Alpha thalassemia results in an excess of beta globins, which leads to the formation of beta globin tetrameters (β4) called haemoglobin H. These tetrameters are more stable and soluble, but under special circumstances can lead to haemolytic, generally shortening the life span of the red cell. Conditions of oxidant stress cause Hgb H to precipitate, interfering with membrane function and leading to red cell breakage. Haemoglobin H-Constant Spring disease is a more severe form of this haemolytic disorder. The most severe thalassemia is alpha thalassemia major, in which a foetus produces no alpha globins, which is generally incompatible with life.
HUMAN IMMUNODEFICIENCY VIRUS (HIV)
HIV stands for human immunodeficiency virus. If left untreated, HIV can lead to the disease AIDS (acquired immunodeficiency syndrome).
Unlike some other viruses, the human body can’t get rid of HIV completely. So once you have HIV, you have it for life.
HIV attacks the body’s immune system, specifically the CD4 cells (T cells), which help the immune system fight off infections. If left untreated, HIV reduces the number of CD4 cells (T cells) in the body, making the person more likely to get infections or infection-related cancers. Over time, HIV can destroy so many of these cells that the body can’t fight off infections and disease. These opportunistic infections or cancers take advantage of a very weak immune system and signal that the person has AIDS, the last state of HIV infection.
No effective cure for HIV currently exists, but with proper treatment and medical care, HIV can be controlled. The medicine used to treat HIV is called Anti Retro-Viral Therapy or ART. If taken the right way, every day, this medicine can dramatically prolong the lives of many people with HIV, keep them healthy, and greatly lower their chance of transmitting the virus to others. Today, a person who is diagnosed with HIV, treated before the disease is far advanced, and stays on treatment can live a nearly as long as someone who does not have HIV.
The only way to know for sure if you have HIV is to get tested. Testing is relatively simple. You can ask your health care provider for an HIV test. Many medical clinics, substance abuse programs, community health centres, and hospitals offer them too. You can also buy a home testing kit at a pharmacy or on-line.
ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS)
AIDS stands for acquired immunodeficiency syndrome. AIDS is the final stage of HIV infection, and not everyone who has HIV advances to this stage.
AIDS is the stage of infection that occurs when your immune system is badly damaged and you become vulnerable to opportunistic infections. When the number of your CD4 cells falls below 200 cells per cubic millimeter of blood (200 cells/mm3), you are considered to have progressed to AIDS. (Normal CD4 counts are between 500 and 1,600 cells/mm3.) You can also be diagnosed with AIDS if you develop one or more opportunistic infections, regardless of your CD4 count.
Without treatment, people who are diagnosed with AIDS typically survive about 3 years. Once someone has a dangerous opportunistic illness, life expectancy without treatment falls to about 1 year. People with AIDS need medical treatment to prevent death.
WHERE DID HIV COME FROM?
Scientists identified a type of chimpanzee in Central Africa as the source of HIV infection in humans. They believe that the chimpanzee version of the immunodeficiency virus (called simian immunodeficiency virus, or SIV) most likely was transmitted to humans and mutated into HIV when humans hunted these chimpanzees for meat and came into contact with their infected blood. Studies show that HIV may have jumped from apes to humans as far back as the late 1800's. Over decades, the virus slowly spread across Africa and later into other parts of the world. We know that the virus has existed in the United States since at least the mid- to late 1970's.