Use in clinical context
Some genetic conditions are apparent from birth, while others develop over time and are diagnosed later in life. In some cases, there is a recognisable family history, with many people in the family affected with the same condition. In other cases, there will only be one person in the family who has the genetic condition.
The variant in the genome causing the condition can be anything from a change to a single base of DNA, for example in sickle cell disease, right up to large structural changes in the chromosomes or change in chromosomal number, for example in Down syndrome.