this book is the fruit of extensive study of the genetic cause behind neonatal jaundice (NJ) in an area studied for the first time similarly, the results and suggestions spot the lite to the real cause behind NJ other than physiological and pathological causes. ugt1a1 is the gene responsible for bilirubin, some anticancer drugs and other toxic hydrophobic substances excretion therefore it's assessment is important not only during the neonatal,postnatal age but life long. furthermore it is opens a window for prenatal diagnosis of genetic diseases and syndromes like grigler-najar syndrome. this book support healthcare organization and subsequent investigators with genetic information and methodology about the nature of jaundice to built a gold-standard strategy for treatment and control of jaundice and anemia .