What Causes Thalassemia? And The Effects

Thalassemia is a group of inherited blood disorders that affect the body's ability to produce hemoglobin and red blood cells - patients have a lower-than-normal number of red blood cells in their bodies and too little hemoglobin. In many cases the red blood cells are too small.

Our red blood cells carry hemoglobin. Hemoglobin, a protein, carries the oxygen we breathe in through our lungs and transports it to the rest of the body.

A spongy material inside some of our bones - bone marrow - uses iron that our body takes from food and makes hemoglobin.

The bone marrow of people with Thalassemia does not produce enough healthy hemoglobin or red blood cells, which causes anemia and fatigue, because the body is short of oxygen. In more severe Thalassemia cases, the patient's organs may be damaged, there is restricted growth, heart failure, liver damage, and even death.

People with mild thalassemia may not require any treatment at all. In more severe forms of the disease, the patient may need regular blood transfusions. Doing plenty of exercises and eating a healthy diet can help some of the symptoms of thalassemia, especially fatigue.

Two alpha globin and two beta globin protein chains make up hemoglobin. There are two types of thalassemia:

Alpha Thalassemia

The alpha thalassemia patient's hemoglobin does not produce enough alpha protein. This type is commonly found in southern China, Southeast Asia, India, the Middle East, and Africa.

To make alpha globin protein chains we need four genes, two on each chromosome 16. We get two from each parent. If at least one of these genes is missing, it produces alpha thalassemia.

The severity of thalassemia depends on how many genes are faulty.

• One faulty (mutated) gene - there are either no symptoms at all, or they are very mild. A person who is apparently "healthy" and has a child with symptoms of thalassemia is known as a Silent Carrier. This type is also known as alpha thalassemia minima, or 2 trait.


• Two mutated genes - the patient will have mild anemia. Also known as alpha thalassemia minor, or 1 trait.


• Three mutated genes - the patient will have hemoglobin H disease, i.e. chronic anemia. A person with hemoglobin H disease needs regular blood transfusions throughout his/her life.


• Four genes are mutated - the patient has alpha thalassemia major, the severest form of this type of thalassemia. Fetuses with four mutated genes cannot produce normal hemoglobin and do not survive. Blood transfusions given to the fetus have a low success rate. This type of thalassemia is also known as hemoglobin Bart hydrops fetalis.

Beta Thalassemia

We need two globin genes to make beta globin chains. We get one from each parent. If one or two of these genes are faulty, it produces beta thalassemia.
Severity of beta thalassemia also depends on how many genes are mutated:

• If one globin gene is mutated - the patient may have Beta thalassemia minor.
• If both globin genes are mutated - the patient may have either moderate or severe symptoms (Colley's anemia).

Beta thalassemia is much more common among people of Mediterranean ancestry, hence its other name, Mediterranean anemia. It is also more prevalent in North Africa and West Asia. Sixteen percent of the people in the Maldives, some islands in the Indian Ocean, are carriers.

What are the Signs and Symptoms Of Thalassemia?

Signs And Symptoms Of Beta Thalassemia

The majority of infants with beta thalassemia will not have symptoms until they reach six months, because they start off with a different type of hemoglobin called fetal hemoglobin. After the age of six months "normal" hemoglobin starts replacing the fetal one. People with thalassemia mainly have anemia-like symptoms.

• Jaundice
• Fatigue
• Pale skin
• Cold hands and feet
• Shortness of breath
• Poor feeding
• Delayed growth
• Skeletal deformities - in some cases as the body tries to produce more bone marrow
• Too much iron - the body will try to absorb more iron to compensate. Iron may also accumulate from blood transfusions. Excessive iron can harm the spleen,heart and liver
• Greater susceptibility to infections
• Delayed puberty

Signs And Symptoms Of Alpha Thalassemia

The majority of children with hemoglobin H are generally healthy. Symptoms will range from mild to moderate anemia.

• Fatigue
• Drowsiness
• Chest pain
• Pale skin
• Cold hands and feet
• Headaches
• Dizziness and feeling faint
• Shortness of breath

If treated properly by a good doctor, and the child with Hemoglobin H follows a healthy diet and is physically active, he/she will not become ill more frequently than other kids.

Illnesses may last longer and symptoms may be more severe compared to other children. Some patients may need blood transfusions when they are ill.

Patients with Hemoglobin H have a higher risk of gallstones and an enlarged spleen.

Most fetuses with alpha thalassemia major die before birth; those that manage to survive until the end of pregnancy are usually stillborn. An ultrasound scan can usually detect hydrops fetalis; the fetus will have excessive accumulation of fluids.

Diagnosing thalassemia

Most children with moderate to severe thalassemia are diagnosed by the end of their second year. People with no symptoms may not realize until they have a child with thalassemia and are then diagnosed as carriers.
If the doctor suspects thalassemia, certain blood tests may be ordered:

• A complete blood count (CBC) - to measure hemoglobin levels, quantities of red blood cells and their size. Not only do patients with thalassemia have less hemoglobin than normal, their red blood cells may be particularly small.


• A reticulocyte count - this blood test measures how fast red blood cells (reticulocytes) are being made by the bone marrow and released into the blood. Reticulocytes are usually in the bloodstream for approximately two days before they develop into mature red blood cells. Between 1% to 2% of a healthy person's red blood cells are reticulocytes.


• Iron - studies of iron will help the doctor determine whether the anemia is caused by thalassemia or iron deficiency. For people with thalassemia, iron deficiency is not the cause.


• Genetic testing - DNA analysis will help either diagnose thalassemia or tell whether a person is carrying faulty hemoglobin genes.

Prenatal testing for thalassemia - to find out whether the fetus has thalassemia and how severe it might be. The following tests may be done:

Chorionic villus sampling - a piece of the placenta is taken out and checked in the laboratory. This is usually done at the end of the first trimester, around the 11th week of pregnancy.

Amniocentesis - a sample of amniotic fluid is taken. This usually occurs during the 16th week of pregnancy. Amniotic fluid is a clear, slightly yellowish liquid that surrounds the fetus.

What are the treatment options for thalassemia?

• Blood transfusions - this is done to replenish hemoglobin and red blood cell levels. Patients with moderate to severe thalassemia will have repeat transfusions every 4 months, while those with more severe disease may require transfusions every two to four weeks. Patients with mild symptoms may require occasional transfusions when they are ill or have an infection.


• Iron chelation - involves removing excess iron from the bloodstream. Sometimes blood transfusions can cause iron overload. Iron overload is bad for the heart and some other organs. Patients may be prescribed subcutaneous (injected under the skin) deferoxamine or oral (taken by mouth) deferasirox.

• Bone marrow transplant - also called a stem cell transplant. Bone marrow is a spongy tissue that exists in the hollow centers of large bones. Bone marrow cells produce red and white blood cells, hemoglobin and platelets.
  
  Doctors say that a bone marrow transplant (from a compatible donor) is the most effective treatment. However, there are significant risks.


• Surgery - some patients with bone abnormalities may require surgery.

What are the complications of thalassemia?

The most common complications include:

• Iron overload - this may be because of the frequent blood transfusions or the disease itself.
  
  Iron overload raises the risk of hepatitis (swollen liver), fibrosis (enlarged liver) and cirrhosis (liver becomes progressively damaged by scarring).
  
  The endocrine system includes glands that produce hormones. The pituitary gland is particularly sensitive to iron overload and can become damaged, which may lead to delayed puberty and restricted growth. Later on after puberty the patient may be at a higher risk of developing diabetes, and having either an underactive or overactive thyroid gland.

Iron overload raises the risk of arrhythmias (abnormal heart rhythms) and congestive heart failure.


• Enlarged spleen (splenomegaly) - also known as hypersplenism. The spleen recycles red blood cells. In patients with thalassemia the red blood cells may have an abnormal shape, making it harder for the spleen to recycle them; the red blood cells accumulate in the spleen, making it grow. An enlarged spleen can become overactive - it starts destroying healthy blood cells the patient receives during transfusions. Sometimes the patient may need a splenectomy (surgical removal of the spleen).


• Infection - if the patient has had his/her spleen removed, there is a greater risk of infection.


• Bone deformities - in some cases the bone marrow expands, which deforms the bone around it. The bones of the skull and face may be affected. As the bone marrow expands, the bone around it becomes brittle, increasing the risk of fracture.

What is the life expectancy for someone with thalassemia?

According to the American Academy of Family Physicians, a patient with thalassemia trait has a normal life expectancy. Those with beta thalassemia major, on average live 17 years and generally die before their thirtieth birthday.

The majority of deaths are caused by the heart complications of iron overload.

SOURCE:  http://www.medicalnewstoday.com