Ethnicity Based Carrier Screening

Some recessive genetic conditions are known to occur with an increased frequency in certain ethnic groups. A person is called a ‘carrier’ when they have a silent genetic trait that does not cause any medical symptoms. When both parents are carriers of the same recessive disease, there is a 1 in 4 (25%) chance that the pregnancy will inherit the trait from both parents and have the disease, a 1 in 2 (50%) chance that the pregnancy will inherit the trait from only one parents and be a carrier, like the parents, or a 1 in 4 (25%) chance that the pregnancy will not inherit the trait from either parent and will not be a carrier or have disease.

Even when there is no obvious family history of a disease, there is still a risk that any individual may be a carrier for a recessive disease based ethnic background. Carrier status for a recessive disease is commonly passed silently from generation to generation. Frequently, carriers are identified only by a specific genetic test. Following is a table listing some of the more common diseases and carrier frequencies in different ethnic groups