A family medical history is important because many medical problems run in families. Inherited diseases could strike early in childhood, or later in life. Conditions passed down the bloodline include diabetes, heart disease, and cancer. Other diseases, including most infections, are not passed on. An understanding of heredity will clarify how these diseases are passed on. Every cell in our body has long-stranded DNA chemicals called chromosomes, which are passed from parent to offspring. These chromosomes are studded with genes like beads on a string. Genes are what produce hereditary diseases, but they also give us physical characteristics such as hair and eye color.

Some genetic diseases, such as Huntington’s Disease, are caused when a gene is inherited from father or mother. Other diseases, such as sickle cell anemia and cystic fibrosis, are caused when the gene comes from both father and mother. Other conditions, such as diabetes and heart disease, require a complex mixture of perhaps 5 to 10 genes inherited from father and/or mother.

Some cancers such as breast cancer run in families, but not all cases of breast cancer are hereditary. BRCA-1 and BRCA-2 are two genes that cause breast cancer? they also cause ovarian and other cancers. Cancers from single genes include multiple endocrine neoplasia and Li-Fraumeni syndrome, which are rare.

Not everyone with a family history of cancer or heart disease will develop the disease. By the same token, people can develop a disease even if that disease is not in their bloodline. Someone with a family history of disease is at increased risk for that disease, while someone without a family history is at decreased risk. The family medical history determines risk of getting a disease, but not a certainty of affliction (in most cases).

Your doctor needs to know your family medical history to determine your risk of developing an inherited medical problem. A family history of medical problems is an important part of a person’s medical history.