Babies born with tetralogy of fallot are called Blue babies. Blue babies syndrome is a condition some babies are born with or develop early in life. It is characterized by an overall skin color with a blue or purple tinge, called cyanosis. The bluish appearance is most noticeable where the skin is thin, such as the lips, earlobes, and nail beds. The infant is born with a congenital heart defect that causes a bluish coloration of the skin as a result of deoxygenated blood (Cyanosis).<span />