In medicine, a family history consists of information about disorders that a patient's direct blood relatives have suffered from. Genealogy typically includes very little of the medical history of the family, but the medical history could be considered a specific subset of the total history of a family.
Although often neglected, many doctors glean information on family morbidity of particular diseases (e.g. cardiovascular diseases, autoimmune disorders, mental disorders, diabetes, cancer) to appreciate whether a person is at risk for developing similar problems. Use of a genogram can be helpful in a family history, which is in the format of a family tree.
Family histories may be imprecise because of various possible reasons:
In complex situations, a family tree may be necessary to cover the necessary aspects.
Not all positive family histories imply a genetic cause. If various members of the same family have been exposed to the same toxin, then they may develop similar symptoms without a genetic cause.
If a patient has a strong family history of a particular disorder (or group of disorders), this will generally lead to a lower threshold for investigating symptoms.
In diseases with a known hereditary component, many healthy people are now tested early to prevent the symptoms from developing. This has become accepted in cystic fibrosis, hemochromatosis and various other disorders.