What is the term for testing an adult to see if they carry a gene for a genetic disorder, and thus assess risk to their offspring?

• A. Adult genetic screening
• B. Foetal screening
• C. Genetic profiling
• D. Carrier testing

Answer: (A)

Testing an adult to see if they carry a gene for a genetic disorder and thus assess risk to their offspring is called carrier testing. It specifically looks for carriers of recessive mutations, so that couples can understand the chance their children might be affected. For example, if two carriers have a child, there’s a 25% chance the child will inherit two mutated copies and be affected, a 50% chance the child will be a carrier, and a 25% chance the child will be unaffected. This differs from foetal screening, which checks a fetus for a disorder, and from broader terms like adult genetic screening or genetic profiling, which are not limited to identifying carrier status.