In certain cases, genetic testing can identify mutant alleles that greatly increase a person's chance of developing a disease such as breast cancer or colon cancer. Between 50 and 70% of people with these particular mutations will develop cancer, but the rest will not. Imagine you are either a 30-year-old woman with a family history of breast cancer or a 30-year-old man with a family history of colon cancer (choose one). Each person can undergo genetic testing to identify a mutation that greatly increases susceptibility to the disease. Putting yourself in the place of the person you have chosen, provide answers to the following questions.

If you were the spouse or partner of the person you have selected, would you encourage or would you discourage the person from having the genetic test? Why?

Key Concepts

Genetic Testing

Genetic testing involves analyzing an individual's DNA to identify mutations or variations that may indicate a predisposition to certain diseases. This process can reveal the presence of mutant alleles associated with increased risks for conditions like breast or colon cancer. Understanding the implications of these results is crucial for making informed decisions about health management and preventive measures.

Penetrance

Penetrance refers to the proportion of individuals with a specific genotype who exhibit the associated phenotype or disease. In the context of genetic mutations linked to cancer, a penetrance of 50-70% means that not everyone with the mutation will develop the disease, highlighting the role of other factors such as environment and lifestyle. This concept is essential for understanding the uncertainty surrounding genetic test results.

Informed Decision-Making

Informed decision-making involves weighing the benefits and risks of undergoing genetic testing, considering both the potential outcomes and emotional implications. For individuals with a family history of cancer, understanding the likelihood of developing the disease and the impact of test results on personal and familial health can guide their choices. This process is vital for spouses or partners who may influence or support their loved ones in making these decisions.