Medical Genetics is the application of genetics to medicine. Medical genetics is broad and varied and encompasses many different individual fields, including clinical genetics, biochemical genetics, cytogenetics, molecular genetics, the genetics of common diseases (such as neural tube defects), and genetic counselling. Each of the individual fields within medical genetics is a hybrid. Clinical genetics is a hybrid of clinical medicine with genetics. Biochemical genetics is a hybrid of biochemistry, mainly the biochemistry of amino acids and proteins, with genetics. Molecular genetics is a hybrid of the biochemistry of DNA and RNA with genetics. Cytogenetics is a hybrid of cytology and genetics; it involves the study of chromosomes under the microscope. And genetic counselling is a hybrid of genetics with non-directional counselling. This book presents leading-edge research on medical genetics as well as on Down's syndrome.