Predictive (Presymptomatic) Genetic testing in pediatrics
Children may be referred because they are at increased risk of developing a genetic disorder in childhood or adult life (i.e the individual is clinically normal now).
n If the condition is likely to manifest in childhood (e.g. Duchenne muscular dystrophy) or if there are useful medical interventions available in childhood (e.g. screening by colonoscopy for colorectal tumours in children at risk of familial adenomatosis polyposis coli), then genetic testing is appropriate in childhood.
n If the child is at risk of a late-onset and untreatable disorder (e.g. Huntington disease), then deferring genetic testing until the child becomes an adult, or at least sufficiently mature to be actively involved in seeking the test and can make the decision for himself/herself, is usually preferred.
n If the child is not at risk of developing the condition but may be a carrier at risk of transmitting the disorder to their future children, then there is also a good case for deferring testing until the young person can participate actively in the decision. There may be less at stake with these reproductive carrier tests than with predictive tests for untreatable disorders, but there are still good grounds for caution and for careful discussion before proceeding with such tests.
These difficult issues are often best handled through a process of genetic counselling supporting open and sustained communication within the family and especially between parents and children.
Predictive testing is not usually offered without a formal process of genetic counselling over more than one consultation with time built in for reflection. Written consent for predictive testing is required by most laboratories.
So, Presymptomatic testing of disorders which manifest in adult life should not be performed until the individual can consent on their own behalf unless there is clear clinical benefit from testing earlier.
