predictive testing
Predictive testing looks ahead. It is done in a healthy person to estimate the chance they will develop a genetic condition later in life — reading the genome for clues about a future that has not yet arrived, often because the condition runs in the family.
For some disorders the result is close to certain: inheriting the causative variant for a fully penetrant dominant condition means the disease is very likely to develop given enough time. For most conditions, though, a variant raises risk without sealing fate, giving a probability rather than a verdict.
Because such knowledge can be life-shaping yet sometimes unactionable, predictive testing is approached with particular care. Counseling before and after is standard, especially for serious adult-onset conditions where there may be no prevention or cure, and the choice to be tested is deeply personal.
An adult whose parent had Huntington disease may choose predictive testing to learn whether they inherited the expanded repeat — a result that is informative but for which there is as yet no cure.
Predictive testing weighs the value of knowing against the absence of a cure.