Articles


Thalassemia

Posted at August 18, 2011 | By : | Categories : Articles | 2 Comments

Mother and her child with Thalassemia

Thalassemia is a group of inherited blood disorders in which the body makes an abnormal form of hemoglobin leading to reduced red blood cells function.

All types of thalassemias are considered quantitative diseases of hemoglobin, because the quantity of hemoglobin produced is reduced and may be absent.

Thalassemia is a genetic disease that exhibits autosomal recessive inheritance, although there are some exceptions.

Generally, thalassemias are prevalent in populations that evolved in humid climates where malaria was endemic. It affects all races, as thalassemias protected these people from malaria due to the blood cells’ easy degradation.

Thalassemia is common in populations of indigenous ethnic minorities of Upper Egypt such as the Beja , Hadendwa and also peoples of the Nile Delta, Red Sea Hill Region and especially amongst the Siwans.

 

Genetics:

Hemoglobin is made of two proteins: Alpha globin and beta globin. Thalassemia occurs when there is a defect in a gene that helps control production of one of these proteins.

 

  • Alpha thalassemia occurs when a gene or genes related to the alpha globin protein (HBA1 or HBA2 genes on chromosome 16) are missing or mutated.

One gene mutation: No clinical effect

Two gene mutation: Mild hypochromic anemia

Three gene mutation: Hb H disease with moderate anemia, splenomegaly

Four gene mutation: Bart’s Hb which can’t carry O2 and is incompatible with life.

  • Beta thalassemia occurs when gene defects (in HBB gene on chromosome 11) affect production of the beta globin protein.

One gene mutation: Beta thalassemia trait or thalassemia minor with mild signs and symptoms.

Two gene mutation: Cooleys anemia or thalassemia major with moderate to severe signs and symptoms.

Note: – Beta thalassemia intermedia : Describes the disease in individuals who have moderate anemia symptoms less than thalassemia major and more than thalassemia triat.

 

– Thalassemia can co-exist with other hemoglobinopathies as hemoglobin E/thalassemia, hemoglobin S/thalassemia and hemoglobin C/thalassemia.

 

Risk Factors:

1- Family history of the disease.

2- Certain ancestry as the disease is more common in Italian, Greek, and Middle Eastern.

 

Symptoms and signs:

The symptoms and signs of thalassemia depend on the type and severity of the disease; some babies show signs and symptoms of thalassemia at birth, while others may develop signs or symptoms during the first two years of life. Some people who have only one affected hemoglobin gene don’t experience any thalassemia symptoms.

 

Symptoms and signs of thalassemia may also include:

1-Face bone deformities “Thalassemia facies”

2-Fatigue

3-Weakness

4-Growth Failure

5-Shortness of breath “Dyspnea”

6-yellowish discoloration of skin “Jaundice”

7- Abdominal swelling “Splenomegaly”

 

Complications:-

1- Iron overload either through the disease itself or through the recurrent blood transfusion.

2- Increased infection rate due to either splenctomy or recurrent blood transfusion.

3- Bone deformities due to bone marrow expansion increasing the chance of bone fracture.

4- Splenomegaly leading to a reduction in red blood cell life.

5- Heart disorders as congestive heart failure and arrhythmias.

 

 Diagnosis:-

Patient suffering from mild thalassemia can’t experience any symptoms for it and can be diagnosed through random examination or test.

Physical examination may show the signs of the disease especially splenomegaly in moderate to severe cases.

Complete blood picture is a must in diagnosis of thalassemia showing microcytic hypochromic anemia in addition to abnormal red blood cell shape, also blood film can show the target cells.

Hemoglobin electrophoresis can show the abnormal form of hemoglobin with increased ratio for HbF and HbA2 , now there is a test called mutational analysis by which we can diagnose anemia even if it wasn’t diagnosed by hemoglobin electrophoresis.

Xray findings include hair end appearance for the skull and thin cortex and wide medulla for long bones.

 

Treatment:-

Treatment of a case of thalassemia depends on its type and the severity of the condition.

Usually in mild cases no treatment is needed but blood transfusion can be done occasionally.

In moderate to severe cases blood transfusion is needed every few weeks in addition to desferal , if the blood transfusion requirement is increased splenectomy can be done.

Recently many studies have been done on stem cell therapy or transplantation and its effectiveness in treating thalassemia.Thalassemia is a group of inherited blood disorders in which the body makes an abnormal form of hemoglobin leading to reduced red blood cells function.

All types of thalassemias are considered quantitative diseases of hemoglobin, because the quantity of hemoglobin produced is reduced and may be absent.

Thalassemia is a genetic disease that exhibits autosomal recessive inheritance, although there are some exceptions.

Generally, thalassemias are prevalent in populations that evolved in humid climates where malaria was endemic. It affects all races, as thalassemias protected these people from malaria due to the blood cells’ easy degradation.

 


Leave a Comment