Thalassemia
Description
Group of genetic disorders characterized by defective synthesis in one or more of the polypeptide chains needed for hemoglobin (Hb) production
Most commonly occurs as a result of reduced or absent production of alpha or beta chains
Affects Hb production and impairs red blood cell (RBC) synthesis
Alpha-thalassemia more common in Blacks and Asians
Beta-thalassemia more common in Mediterranean populations
Beta-thalassemia classified three ways: major (also known as Cooley’s anemia, Mediterranean disease, and erythroblastic anemia), intermedia, and minor
Pathophysiology
Total or partial deficiency of beta-polypeptide chain production impairs Hb synthesis and results in continual production of HbF, lasting even past the neonatal period.
Normally, immunoglobulin synthesis switches from gamma- to beta-polypeptides at birth; this conversion doesn’t happen in thalassemic infants as their RBCs are hypochromic and microcytic.
Causes
Assessment findings
Thalassemia major
Healthy infant at birth; severe anemia, bone abnormalities, failure to thrive, and life-threatening complications developing during second 6 months of life
Pallor and jaundice (yellow skin and sclera) at ages 3 to 6 months
Splenomegaly or hepatomegaly with abdominal enlargement, frequent infections, bleeding tendencies (especially nosebleeds), anorexia
Small body and large head (characteristic features); possibly mental retardation
Features similar to Down syndrome in infants because of thickened bone at the base of the nose from bone marrow hyperactivity
Thalassemia intermedia
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