Clinical genetics is a specialty of medicine that focuses on the diagnosis, prevention, and management of genetic disorders. The family is an important part of [Page 530]a clinical genetics visit in that results of genetic testing may have relevance to the health of not only the patient but also their extended family members. The family history is of critical importance as well, because the health history of others in the extended family tree may give clues to the underlying diagnosis by pointing toward a mode of inheritance that can have a significant role in narrowing down possible diagnoses. Clinical genetics in its present-day form is a relatively new specialty of medicine. The correct chromosome number in humans was described in 1956. Developments in the science ...