|Care of the Child with Thalessemias|
Hemaglobin is a tetramer protein (meaning it has 4 heme groups)
2 alpha protein subunits & 2 Beta protein subunits
There is an iron atom in the center of each heme group
Function: Reversible binding of Oxygen
Thalessemias are the MOST common genetic disease worldwide. They are a group of disorders with ineffective RBC production (impairment in rate of globin chain synthesis) resulting in microcytic anemai with ineffective erythropoiesis
Inherited defect in Beta chain synthesis
Unaffected alpha chain continues to be produced and accumulates in the RBC and interferes with normal maturation and contributes to the RBC destruction. The excess alpha chains denature to form precipitates called Heinz bodies in the RBC precursors in the boen marrow. The Hdinz bodies impair DNA synthesis & damage the RBC membrane which can lead to severe hypochromic microcytic anemia.
Chronic transfusions are required with an inevitable iron overload. 50% of untreated patients die by 5 years of age.
The more severe the imbalance between alpha & beta hemoglobin the worse the disease
Heterozygous = Beta Thalassemia Minor (mose normal Hgb and malarial protection)
Homozygous = Beta Thalassemia Major (severe, transfusion-dependent, early onset at 6-9 months of age, growth retardation)
Every body system is affected
The x-ray on the right above demonstrates bone marrow hyperplasia of the skull.
Severe anemia with MCV in the 50-60 range (microcytosis) also hypochromic
On smear will be target cells and hardly any normal cells
Oral Chelator? So far no safe alternative
Spenectomy (for hypersplenism) as indicated by:
Stem cell transplantation - Bone Marrow Transplant