The procedure whereby advice is given about the risks of a genetic disorder and the various options that are open to the individual at risk. This may often involve establishing the diagnosis in the family, as this would be a prerequisite before giving any detailed advice. Risks can be calculated from simple Mendelian inheritance (see MENDELISM) in many genetic disorders. However, in many disorders with a genetic element, such as cleft lip or palate (see CLEFT PALATE), the risk of recurrence is obtained from population studies. Risks include not only the likelihood of having a child who is congenitally aﬀected by a disorder, but also, for adults, that of being vulnerable to an adult-onset disease.
The options for individuals would include taking no action; modifying their behaviour; or taking some form of direct action. For those at risk of having an aﬀected child, where prenatal diagnosis is available, this would involve either carrying on with reproduction regardless of risk; deciding not to have children; or deciding to go ahead to have children but opting for prenatal diagnosis. For an adult-onset disorder such as a predisposition to ovarian cancer, an individual may choose to take no action; to take preventive measures such as use of the oral contraceptive pill; to have screening of the ovaries with measures such as ultrasound; or to take direct action such as removing the ovaries to prevent ovarian cancer from occurring.
There are now regional genetics centres throughout the United Kingdom, and patients can be referred through their family doctor or specialists.