Cascade genetic counseling and testing in hereditary syndromes: inherited cardiovascular disease as a model: a narrative review

Inherited cardiovascular diseases cover the inherited cardiovascular disease familial hypercholesterolemia and inherited cardiac diseases, like inherited cardiomyopathies and inherited arrhythmia syndromes. Cascade genetic counseling and testing in inherited cardiovascular diseases have had three decades of academic attention. Inherited cardiovascular diseases affect around 1-2% of the population worldwide and cascade genetic counseling and testing are considered valuable since preventive measures and/or treatments are available. Cascade genetic counseling via a family-mediated approach leads to an uptake of genetic counseling and testing among at-risk relatives of around 40% one year after identification of the causal variant in the proband, with uptake remaining far from complete on the long-term. These findings align with uptake rates among relatives at-risk for other late onset medically actionable hereditary diseases, like hereditary cancer syndromes. Previous interventions to increase uptake have focused on optimizing the process of informing relatives through the proband and on contacting relatives directly. However, despite successful information dissemination to at-risk relatives, these approaches had little or no effect on uptake. The limited research into the barriers that impede at-risk relatives from seeking counseling has revealed knowledge, attitudinal, social and practical barriers but it remains unknown how these factors contribute to the decision-making process for seeking counseling in at-risk relatives. A significant effect on uptake of genetic testing has only been reached in the setting of familial hypercholesterolemia, where active information provision was accompanied by a reduction of health-system-related barriers. We propose that more research is needed on barriers -including health-system-related barriers- and how they hinder counseling and testing in at-risk relatives, so that uptake can be optimized by (adjusted) interventions.