Testing to confirm a clinical diagnosis

When a genetic test is requested to confirm a clinical diagnosis
in a child or adult, specialist genetic counselling may not be
requested until after the test result. It is therefore the
responsibility of the clinician offering the test to inform the
patient (or the parents, if a child is being tested) before the test
is undertaken, that the results may have genetic as well as
clinical implications. Confirming the diagnosis of a genetic
disorder in a child, for example, may indicate that younger
siblings are also at risk of developing the disorder. For late
onset conditions such as Huntington disease, it is crucial that
samples sent for diagnostic testing are from patients already
symptomatic, as there are stringent counselling protocols for
presymptomatic testing