This book describes newborn screening as a public health program for the early detection of genetic disorders. It presents the recommended uniform screening panel (RUSP), a list of genetic disorders recommended by the U.S. government for states to include in newborn screening programs. The author describes the categorization of RUSP genetic disorders, discusses the symptoms and health complications of examples from each category, and explains clinical laboratory tests used for newborn screening. The book explores the underlying molecular genetic causes of genetic disorders, and how this information is used for genetic testing during newborn screening and diagnosis. It presents the patterns of inheritance of monogenic genetic disorders, and uses hypothetical family scenarios to illustrate them. Treatments and therapies for selected RUSP genetic disorders are described that illustrate the benefits of early diagnosis. The book describes future prospects for the prevention, diagnosis, and treatment of genetic disorders detected by newborn screening, including experimental drug treatments, the possibility of newborn genome sequencing, and gene therapy.