This document of the European Society of Human Genetics contains recommendations regarding responsible implementation of expanded carrier screening. Carrier screening is defined here as the detection of carrier status of recessive diseases in couples or persons who do not have an a priori increased risk of being a carrier based on their or their partners' personal or family history. Expanded carrier screening offers carrier screening for multiple autosomal and X-linked recessive disorders, facilitated by new genetic testing technologies, and allows testing of individuals regardless of ancestry or geographic origin. Carrier screening aims to identify couples who have an increased risk of having an affected child in order to facilitate informed reproductive decision making. In previous decades, carrier screening was typically performed for one or few relatively common recessive disorders associated with significant morbidity, reduced life-expectancy and often because of a considerable higher carrier frequency in a specific population for certain diseases. New genetic testing technologies enable the expansion of screening to multiple conditions, genes or sequence variants. Expanded carrier screening panels that have been introduced to date have been advertised and offered to health care professionals and the public on a commercial basis. This document discusses the challenges that expanded carrier screening might pose in the context of the lessons learnt from decades of population-based carrier screening and in the context of existing screening criteria. It aims to contribute to the public and professional discussion and to arrive at better clinical and laboratory practice guidelines.

BackgroundCarrier screening is generally performed with the aim of identifying healthy couples at risk of having a child affected with a monogenic disorder to provide them with reproductive options. Expanded carrier screening (ECS), which provides the opportunity for multiple conditions to be screened in one test, offers a more cost-effective and comprehensive option than screening for single disorders. However, implementation of ECS at a population level would have implications for genetic counseling practice.MethodsWe conducted semi-structured interviews with sixteen European clinical and molecular geneticists with expertise in carrier screening to explore their views on the implementation of ECS in the clinical setting.ResultsUsing inductive content analysis, we identified content categories relevant to the pre- and post-test settings. Participants believed ECS would ideally be targeted at couples before pregnancy. There was some disagreement regarding the acceptability of performing ECS in individuals, with several participants actively opposing individual-based screening. In addition, participants discussed the importance of ensuring informed and voluntary participation in ECS, recommending measures to minimize external pressure on prospective parents to undergo testing. A need for adequate counseling to foster informed, autonomous reproductive decision-making and provide support for couples found to be at risk was emphasized.ConclusionsPractical challenges in optimizing pre-test education and post-test counseling should not be underestimated and they should be carefully addressed before implementing ECS in the clinical setting.

Although a limited ECS offer is practical, it also raises concerns over equality in access to screening. A comprehensive risk-benefit analysis is needed to determine the desirability of systematic population-wide ECS.

Aims: To explore the views of the Belgian public on various topics surrounding genetics and genetic testing (GT). Materials and Methods: A written questionnaire was administered to visitors of the annual cartoon festival in Knokke-Heist, Belgium, during the summer of 2014. The main theme of the festival was challenges and progress in human genetics and it was attended by more than 100,000 visitors. Results: The survey was completed by 1182 respondents, resulting in a demographically diverse sample with a mean age of 48.5 years. Our respondents expressed moderate interest in predictive GT, with 39.1% willing to learn about their predisposition to diseases through GT and 49.5% indicating interest in getting tested exclusively for treatable/preventable diseases. We observed higher interest in GT for reproductive purposes, such as preconception screening for recessive disorders (53.8%) and prenatal GT (60.7%). A substantial minority (46.4%) of the respondents were worried that GT could further stigmatize people with disabilities, while 39.7% believed that carrier screening for recessive diseases would lead to an inferior image of people affected by them. Conclusion: Paying due attention to the attitudes, beliefs, and concerns of the general public is important to ensure ethically sound and socially acceptable implementation of new genetic technologies.