In recent years, doctors and scientists have made great strides in increasing our knowledge of hundreds of genetic disorders. Many serious disorders have now been identified as having a genetic basis, and treatment for birth defects has improved substantially.The Encyclopedia of Genetic Disorders and Birth Defects, Third Edition offers lay readers and professionals alike the most comprehensive single-volume reference to congenital disorders and birth defects. This accessible volume contains more than 1,000 expertly written entries - including more than 135 new entries and more than 60 revised entries, extensive appendixes providing updated tables of statistics and directories of service and support groups, and a concise introductory history of human genetics. This new edition has been extensively updated to reflect the most current research.