Cascade counselling and testing. Recommendations of the European Society of Human Genetics.

Cascade testing (CT) is an effective instrument for identifying an index patient's relatives at high risk of a heritable condition enabling informed decision-making on preventive interventions and reproductive choice. However, CT remains underutilised and faces barriers. Discussions are ongoing on how to optimise informing family members and testing uptake in a responsible manner. The European Society of Human Genetics (ESHG) contributes to this debate and provides recommendations based on an ethical analysis of when CT is justified, or may be less compelling, considering proportionality and the judicious use of finite resources. ESHG underscores the strong consensus regarding the 'moral architecture' of CT in cases of a high risk of serious, avoidable harm. In such cases, a more active approach towards CT is suggested, including a more directive approach in counselling, more active support for the proband, direct contacting, and balancing confidentiality when this is necessary to avoid a high risk of serious harm, taking account of national regulations and jurisdictions. In contrast, more caution is advised in more complex cases where the balance of benefits and harms of CT is less clear, such as when penetrance is low, and actionability or medical treatment is limited. This more cautious approach does not call for directivity, direct contact or the relaxing of medical confidentiality. The focus, then, shifts to cascade counselling, rather than cascade testing. In some cases, CT may not be proportional or appropriate given the balance between benefits and harms, also in view of available resources.