In every family, parents can simply look in the mirror to get an idea of what their children will be like.
Parents pass half of their genes on to their children, influencing such characteristics as eye color, health status and personality. For better or worse, family members will share certain features.
It has long been recognized that cancer falls into the category of features that can run in the family.
Because cancer is unfortunately common, most families are touched by cancer to some degree. Some families, however, have unusually high rates of cancer.
In the last two decades, research has narrowed in on specific genes that play a large role in cancer development. Changes in these genes, called mutations, prevent the gene from working properly.
As a result, cell growth may become uncontrolled, leading to cancer. Families who carry one of these mutations will have several family members who are at a high risk for cancer.
This pattern can be seen with colorectal cancer. The most common example is Lynch syndrome, a medical condition that increases cancer risk.
Lynch syndrome is caused by a mutation in one of the mismatch repair (MMR) genes, and the mutation can be passed down from one generation to the next. The greatest concern for people with a MMR gene mutation is the high risk to develop colorectal, endometrial (uterine), ovarian and/or gastric (stomach) cancers.
Because of this predisposition to cancer, proper medical management becomes extremely important. Established health care guidelines are recommended for people with Lynch syndrome, including annual colonoscopies and endoscopies. Close surveillance greatly reduces cancer risk for people with Lynch syndrome.
The diagnosis of Lynch syndrome relies heavily on family history and genetic testing. A genetic counselor helps identify patients who may have Lynch syndrome and meets with them to evaluate their risk, offer testing, and guide them through the process.
Knowledge of family medical history can be the clue to recognizing genetic conditions such as Lynch syndrome, and appropriate medical care can dramatically affect health.
Genetic information is becoming increasingly important in health care, a fact that patients and physicians alike should keep in mind. Health conditions such as colorectal cancer can be inherited, but also can be managed.
Terah Hansen is a certified genetic counselor at Providence St. Mary Regional Cancer Center.