Thalassemia Minor Causes,Symptoms and Treatment

Thalassemia Minor is the mildest form of the illness. The individuals may be heterozygous and inheriting only one mutant or p-thal gene, which limits the synthesis of beta-peptide chains. Or they may have inherited a genetically distinct abnormality of p-globin chain which produces a milder disease. The gene for alpha chain synthesis is normal. There is usually compensatory increase in delta chain synthesis, leading to levels of Hb A2 being higher than normal. Hemoglobin A2 may be markedly reduced with co-existing iron-deficiency anemia.
Increase in the level of hemoglobin F is inconstant. Production of hemoglobin A is only slightly reduced.
Thalassemia Minor patients have only a very mild anemia, sometimes with abdominal pain and mild icteric, tinge. Thalassemia minor is often confused with iron deficiency anemia and is treated as such, till the correct diagnosis is suspected. Serum iron concentration is on the higher side and iron binding capacity is reduced. Free erythrocyte porphyrin is normal in thalassemia minor (30 microgram/dL of whole blood). This is moderately raised in iron deficiency anemia (30 to 190 ug/ dL of whole blood). This is a useful diagnostic test to differentiate iron deficiency states from thalassemia minor and lead poisoning.
ALPHA-THALASSEMIA-HEMOGLOBIN H DISEASE
The synthesis of alpha-peptide chains is suppressed. Defective alpha chain synthesis effects the production of all the normal hemoglobin viz., A, A2 and F. Four beta-peptide chains polymerise to a tetrameric form giving rise to hemoglobin H. Heterozygous alpha thalassemia is usually very mild and is often not associated with any regular alteration in the hemoglobin pattern in the adult life.
There are possibly two alleles for alpha-thalassemia gene viz., alpha-thalassemia1 causing complete inhibition of alpha chain synthesis and alpha-thai2 causing only impaired synthesis of alpha chains.
Alpha-thalassemia is most prevalent in the countries of South East Asia. The infant is usually normal at birth.

TREATMENT OF THALASSEMIA
Blood transfusion

The mainstay of managing these cases is repeated blood transfusions. An attempt should be made to maintain hemoglobin level above 10-12 g/dL (by hyper transfusion) to ensure active life and adequate growth. Group and type specific, fresh, triple saline washed, packed red cell transfusions are the most desired form of component therapy. These are to be transfused at the rate of 10-15 ml/kg every 2 to 3 weeks. Blood transfusions may result in hemolytic or febrile reactions, transmission of viral infections (HIV1 & 2, Hepatitis B and C, Cytomegalovirus) and iron overload. Routine donor screening for these viral infections is a must. All thalassemics should be vaccinated with Hepatitis B vaccine before starting transfusions. Iron overload results in multiple organ dysfunction due to hemosiderosis and hemochromatosis. Chronic anemia itself is a potent stimulator of iron absorption from the gut. Iron overload can be reduced by regular chelation therapy and reducing iron absorption by keeping the hemoglobin levels high.
Neocyte transfusion

Special cell separators are available for obtaining younger cells with longer life span (neocytes). Infusion of these cells instead of the whole blood increases interval between two transfusions and decreases the transfusion requirement and hence the iron load. Simultaneous removal of older cells (gerocytes) from patient’s circulation by pheresis technique reduces iron load considerably. However, these procedurs are cumbersome, costly and need a lot of expertise.
Chelation therapy

At present only desferrioxamine is available as iron chelating agent in parenteral form. It should be given as continuous subcutaneous infusion in the dose of 25-50 mg/kg/day over a period of 8-12 hours, during the night, by specially designed microinfusion pumps, (at least 5-6 nights per week). The chelation should start by 12-14th transfusion. 100 mg of vitamin C daily should be concurrently administered. Overdose of desferrioxamine results in growth retardation, visual and auditory toxicity. Cataracts have been noted in some children on long term desferrioxamine therapy. Deferiprone (DFP) is an effective oral iron chelating agent with minimal toxicity. It is given in a dose of 75 mg/kg/day in 2-4 divided doses. The most common side-effect is arthropathy. Other oral chelators include pyridoxine hydrazine, HBED and desferrothiocine. These are still under trials.

Splenectomy

Splenectomy is recommended in cases when the transfusion requirement exceeds 250 ml/kg/year of packed red cells. The decision should be deferred as far as possible and if required delayed beyond the age of five years.