<prompt> Defect leading to thalassemia lies in -HaemoglobinOsmotic fragilityRBC membranePlatelets  <response>: Disorders of haemoglobinDisorders of haemoglobin may be of two types : -1. The qualitative defect of haemoglobin hemoglobinopathyHemoglobinopathies are disorders of haemoglobin, characterized by a defect that results in the abnormal structure of one of the globin chain of haemoglobin.Examples are - Sickle cell anemia, HbC, HbE, HbD-Punjab, HbO-Arab, Hb Lepore.2. The quantitative defect of haemoglobinThese disorders are characterized by a defect that results in a decreased rate of synthesis of one of the globin chain of haemoglobin.Example - Thalassemia 