A good starting point is to check for presence of certain genetic conditions in your family. Some ethnic groups have mutations, which is specific to their population. For example Familial Mediterranean Fever (FMF) is an auto-inflammatory disorder that is present in ethnic groups that either originated in Mediterranean region such as Jews, Arabs, Armenians, Italians, Greeks or has been living and exchanging genes in that region for hundreds of years such as Turks. Sickle cell anemia is another example of ethnic genetic disorders.
Also you would know about mutations in your genes if your physician is suspicious of a genetic condition, which exists in general population such as fragile X chromosome or Cystic Fibrosis. In either case you could check for hereditary conditions that could potentially affect you or your family members based on your ethnic or geographical background.