• Diagnostic testing in a child who has features of a genetic disorder, e.g. chromosome analysis in a child with suspected Down syndrome.
• The child is asymptomatic, but is at risk for a genetic condition for which preventive or other therapeutic measures are available, e.g. testing to determine if a child of an affected parent with retinoblastoma (with a known mutation) requires screening by frequent periodic examination under anaesthesia. This is predictive testing and should involve a clinical geneticist.
• The child is at risk for a genetic condition with paediatric onset for which preventive therapeutic measures are not available, e.g. SMA type 1. Involve a clinical geneticist. The decision to undertake a genetic test requires a careful balancing of benefit/harm; each case is assessed on its individual merits. Generally, testing is done at parental discretion after careful discussion.
• An asymptomatic child is at risk for a genetic condition that usually has onset in adult life for which preventive or effective therapeutic measures are not available, e.g. Huntington’s disease.
• Testing for carrier status, e.g. siblings of a child with cystic fibrosis. Practice does vary, but we recommend that testing be deferred until the child is old enough to seek testing in their own right, or at least to take part in the discussion about testing. Parents sometimes request testing of young children without having necessarily thought through the difficulties this may lead to later on. We suggest referral to clinical genetics if parents remain keen to perform carrier test.
Genetic testing of children for the benefit of another family member should not be performed unless testing is necessary to prevent substantial harm to the family member.