Haematopathology: Understanding Thalassemia

Hemoglobin

• The most common type of normal hemoglobin is Hb A.

Thalassemia Minor

• A normal blood film in thalassemia minor is characterized by microcytic hypochromic red blood cells.
• The diagnostic test for beta-thalassemia minor is based on elevated levels of Hb A2.

Fetal Hemoglobin (Hb F)

• The structure of fetal hemoglobin (Hb F) is α2γ2.
• In cases where Hb F is present in 85% of cases, the expected reticulocyte count is low.

Hemoglobin A2 (Hb A2)

• The normal range of Hb A2 is 2-3.5%.
• In beta-thalassemia minor, the level of Hb A2 is increased.

Alpha Thalassemias vs Beta Thalassemia

• Alpha thalassemias are generally less severe than Beta thalassemia clinically.

Alpha Thalassemia

• In individuals with Alpha thalassemia with no alpha genes (α o α o), the clinical phenotype is hydrops fetalis, which is usually lethal.
• Hemoglobin H disease is common in Southeast Asia.
• The only clinical phenotype of alpha thalassemia of clinical significance is Hemoglobin H disease.
• In individuals with Hemoglobin H disease, the clinical feature most unusual to see is a high reticulocyte count.

Thalassemia Intermedia

• The blood picture and clinical presentation of Thalassaemia Intermedia include moderate to severe anemia, jaundice, and splenomegaly.

Thalassaemia Prevention

• The first step recommended for Thalassaemia prevention is premarital screening.
• Following the identification of couples at risk of bearing affected children through premarital screening, genetic counseling and testing are recommended.