Slide 1

EXPLAINING THALASSEMIA

MEI LYN TAN

DR. SARAH SALM
BIO 425, Section 112

DECEMBER 14, 2005

Slide 2

EXPLAINING THALASSEMIA

• Thalassemia is one of the most common inherited genetic diseases.
• This disease is generally found among natives of Africa, Greece, Italy, Southeast Asia, Far East, Middle East and Southern China and in the last decade, North America.

Slide 3

WHAT IS THALASSEMIA?

• Thalassemia is a genetic blood disorder caused by mutated or missing genes.
• DNA consist of segments called genes, which are found in the chromosomes
• Two of these genes are responsible for the production of hemoglobin which is found in the red blood cells.
• Hemoglobin carries the Oxygen supply to the whole body and is essential for the body to function normally.

Slide 4

WHAT IS THALASSEMIA?

• The result of a missing or mutated gene causes the lack or absence of normal hemoglobin production.
• Due to this condition, the individual experiences varying degrees of anemia together with other illnesses that are associated with it.

Slide 5

WHAT HAPPENS IN A PERSON WITH THALASSEMIA?

• Alpha globins are located on Chromosome 16 and are produced by Alpha genes.
• Beta globins are located on Chromosome 11 and are produced by Beta genes.
• These genes contain the ‘blue print’ for making the specific globin chains.
• A balance between the chains produced on Chromosome 16 and 11 is necessary to enable the Hemoglobin to carry out its function efficiently.
• Due to a mutated or missing gene, often the balance has been affected in a person with Thalassemia.
• The amount and the quality of the globin chains produced determines the severity of the type of Thalassemia.

Slide 6

HOW TO DETECT THALASSEMIA?

• Hemoglobin electrophoresis test
• Complete blood count
  • Normal reference range for Hemoglobin readings is 13.2 – 17.1 g/dL.
  • Person with Thalassemia – below 13.2 g/dL.
• Iron level tests

Slide 7

HOW DOES A PERSON GET THALASSEMIA?

• A normal person has 46 Chromosomes, 23 from their father and 23 from their mother.
• All forms of Thalassemia are inherited, passed from parents who carry the mutated Thalassemia gene in their DNA, to their children.

Slide 8

GENETICS OF THALASSEMIA

• The following are the possibilities:
  • If both parents do not carry the Thalassemia disease or trait, then the child would be normal
  • If one parent carries the Thalassemia trait but the other is normal, then the child will have a 50% chance of inheriting the Thalassemia trait.
  • If both parents have the Thalassemia trait, the child will have a 25% chance of inheriting the Thalassemia disease, 50% of inheriting the Thalassemia trait and a 25% chance of being normal.
• It is not medically possible to predict the order of occurrences.

Slide 9

TYPES OF THALASSEMIA

Alpha Thalassemia

• There are four Alpha genes on Chromosome 16
• The variations of Alpha Thalassemia depend on the decreasing Alpha genes.
• Alpha Thalassemia is often categorized into the following :
  • Silent Carrier
  • Alpha Thalassemia trait
  • Hemoglobin H disease
  • Hemoglobin H-Constant Spring
  • Alpha Thalassemia major or more commonly known as Hydrops Fetalis

Slide 10

TYPES OF THALASSEMIA

Beta Thalassemia

• The Beta Thalassemia is caused by mutations in the Beta globin gene.
• According to the Northern California Comprehensive Thalassemia Centre, 80% of these mutations consist of only 20 common types of mutations.
• Majority of Thalassemia incidences are of this form.
• Beta Thalassemia is often categorized into the following :
  • Beta Thalassemia minor or trait
  • Beta Thalassemia intermedia
  • Beta Thalassemia major, often known as Cooley’s Anemia

Slide 11

EFFECTS OF THALASSEMIA

• Mild to severe Anemia
• Individuals with mild Anemia encounter:
  • Shortness of breath
  • Fatigue
• Very often mistakenly diagnosed as having iron deficiency.
• Individuals with severe Anemia encounter
  • Enlarged spleen
  • Enlarged liver
  • Heart palpitations
  • Mild Jaundice
  • Bone formation is defective, usually enlargement of the cheek bones
• Life expectancy and quality of life for individuals with severe Anemia is compromised.

Slide 12

TREATMENT OF THALASSEMIA

• An individual with only the Thalassemia trait would require to have :
  • Regular Doctor visits every 2-6 times a year.
  • Hemoglobin Levels tests
  • Spleen Size
  • Growth and Development Progress
  • Nutrition
  • Bone Formation Abnormalities
• Transfusion
• Bone Marrow Transplant
• Cord Blood Transplant
• Gene Replacement
• Fetal Hemoglobin Manipulation