Thalassemia 

Thalassemias are the commonest hemolytic anaemias or disorder seen in children in India. This is characterised by deficiency  in the synthesis  of one of the normal globin chains of haemoglobins and there is an increased synthesis of foetal haemoglobin (HBF) which alters the ratio of adult and feral haemoglobin.

Two common types of thalassemia are caused by decrease in alpha or beta chains.

Two major form of beta thalassemia are thalassemia minor and thalassemia major. 

Thalassemia minor is associated with decreased beta chain synthesis and is the heterozygous  form of the disease which generally produces little effect on the child except mild anaemia. 

Thalassemia major (Cooley's anaemia, mediteranean anaemia) is associated with absent beta chain synthesis and is the homozygous form of the disease and produces severe anaemia. This is the commonest form of thalassemia.