Student Resources: Student Projects: Mei Lyn Tan
Explaining Thalassemia   view PDF

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