The present book explores the molecular genetics level research of Sickle syndrome,Thalassemia and Iron Deficiency Anemia which was done at department of Hematology, All India Institute of Medical Sciences,New Delhi & APS University Rewa, Madhya Pradesh. Research was funded by Indian Council of Medical Research, New Delhi.Understanding the parameters that modify sickle cell disease severity, enormously useful in treatment decisions. A method to identify patients with prognoses for severe disease allow targeted use of the drug for people who stand most to benefit. The data of study help us to understand more about the status of phenotypic effect in sickle cell anemia patient's population in relation to molecular aspects of sickle cell genome. Pathophysiology of IDA may be altered through the metabolism of iron status with significant differences between heterozygous and those homozygous for the wild-type allele. Effect of HFE,Tf and GST mutation on the phenotype of IDA patients correlate the modulation of IDA and their genetic variation.