A more thorough explanation:

Definition: GMT stands for Genetic-Marker Test. It is a type of test that looks for specific genetic markers in a person's DNA to determine if they have a certain genetic condition or disease.

Example: One example of a genetic-marker test is the BRCA test, which looks for mutations in the BRCA1 and BRCA2 genes that are associated with an increased risk of breast and ovarian cancer.

Explanation: The example illustrates how a genetic-marker test can be used to identify a specific genetic mutation that is linked to a particular disease. By analyzing a person's DNA, doctors can determine if they have the mutation and assess their risk of developing the disease. This information can be used to guide medical decisions and interventions, such as increased surveillance or preventative measures.