Medical genetics is an evolving field. Historically it encompassed only rare Mendelian disorders and chromosome abnormalities with multisystem phenotypes. Because of their medical complexity combined with the risk to other family members and the psychosocial issues that arise when dealing with issues of inheritance, these cases were best handled by geneticists and genetic counselors. Now, a growing number of diseases have been recognized as having a genetic basis, and relegating genetics just to the geneticists and genetic counselors has become more difficult. Moreover, identification of those aspects of genetics that can be incorporated into primary care has become more important. Key to this process is identifying when to refer a patient to a geneticist or a genetic counselor. Many factors come into play, as demonstrated by the following case:
CASE STUDY
A 50-year-old woman of Ashkenazi Jewish ancestry has been given a diagnosis of invasive breast cancer; her mother died of breast cancer at 48 years, and her sister's ovarian cancer was diagnosed at age 52. Based on that history, the woman was at risk of carrying a mutation in BRCA1 or BRCA2, the two genes known to cause hereditary breast and ovarian cancer syndrome.
After meeting with a genetic counselor whose area of expertise was cancer, the patient learned more about what carrying a BRCA1 or BRCA2 mutation meant. If she had such a mutation, each of her three daughters would be at a 50% risk to inherit it as well. Those who carry a BRCA mutation have a 65% to 85% lifetime risk of breast cancer1,2 and an 11% to 54% lifetime risk of ovarian cancer.1,2
The counselor offered genetic testing to determine whether the patient carried a BRCA mutation. In addition to the implications for her daughters, a positive result would mean that the patient herself was at increased risk for developing a second breast cancer and/or ovarian cancer. Given the weight of this information, she and her husband decided that they needed to think about whether they were ready to know more and to share this information while they were in the midst of dealing with the current breast cancer diagnosis and treatment. Several months later the couple decided, for their daughters' sake, to proceed with testing.
After blood was drawn, the patient made an appointment with the genetic counselor to receive the results in person. Two days before that appointment, the patient called to cancel, explaining that she could not handle the information at that time. Several follow-up calls and cancelled appointments later, she came in for her results. (Figure 1 shows her genetic pedigree.) Though not surprised that she tested positive for a BRCA1 mutation, the patient was devastated by the implications this would have for her daughters. The genetic counselor offered to work with the patient to share this information with her daughters and referred her to FORCE: Facing Our Risk of Cancer Empowered, a support group for women at high risk for breast cancer and/or ovarian cancer. Not every scenario involving genetic counseling is as emotionally charged as this one. Still, this patient's story illustrates the additional emotional burden and guilt often associated with hereditary conditions.
