Family history: The family structure and relationships within the family, including information about diseases in family members.

The family history is often recorded in a family pedigree (family tree), which uses conventional symbols. The pedigree provides a ready view of problems or illnesses within the family and facilitates analysis of inheritance patterns. Study of a trait or disease begins with the affected person (the index case). The pedigree is drawn as the relatives are described. One begins with the siblings of the proband and proceeds to the parents; relatives of the parents, including brothers, sisters, nephews, and nieces; grandparents; and so on. At least 3 generations are usually included. Illnesses, hospitalizations, causes of death, miscarriages, abortions, congenital anomalies, and any other unusual features are recorded.