Assessing the Potential Success of Cystic Fibrosis Carrier Screening: Lessons Learned from Tay-Sachs Disease and β-Thalassemia

Abstract

Objective: The objective of this study was to identify factors involved in the success of 2 well-established population-based carrier screening programs – Tay-Sachs disease (TSD) in Ashkenazi Jews and β-thalassemia in Sardinia and Cyprus – and to assess the potential for success of a population-based cystic fibrosis (CF) carrier screening strategy using these factors. Methods: We performed a literature review and key informant interviews. Results: Factors involved in the success of TSD and β-thalassemia carrier screening programs include disease characteristics (well-defined population at risk, severe disease with predictable course, availability of effective treatment), test characteristics (high sensitivity, straightforward interpretation of results), and community characteristics (involvement of community, support of families and advocacy groups, consensus in favor of avoiding affected births). Current CF screening strategies include few of the factors listed above. Unlike TSD and β-thalassemia, the purpose of current CF carrier screening strategies is informed reproductive decision-making, without an explicit goal of reducing disease incidence. Conclusion: When compared to TSD and β-thalassemia, CF is a less favorable candidate for population-based carrier screening. Because of its different purpose, CF carrier screening will require different measures of success than those used for TSD and β-thalassemia carrier screening, and a consensus on the value or success of CF carrier screening may be difficult to achieve.

Factors for successful implementation of population-based expanded carrier screening: learning from existing initiatives: Table 1

“…As described by Laberge et al, 25 consensus in favour of avoiding affected births is one of the factors involved in the success of TSD and β-thalassaemia carrier screening programmes. This consensus would seem crucial for the successful implementation of programmes in which reducing birth prevalence is the explicit aim.…”

“…Successful implementation of TSD screening is partly due to the perceived severity of the disease among the Jewish community, and the involvement of clinicians and community leaders in the development of carrier screening programmes 25 . Carrier screening programmes for the Jewish community are furthermore often funded by the population itself 33 .…”

Do people from the Jewish community prefer ancestry-based or pan-ethnic expanded carrier screening?

“…5,18,19 Factors described to contribute to the high receptiveness of this community towards screening include the close involvement of the community, and consensus in favor of avoiding affected births. 20 Furthermore, half of the respondents planning to have children in our study intended to have a carrier screening test. This finding is difficult to compare with other studies as most studies do not discuss intention but measure uptake in, for example, Dor Yeshorim or high school settings (eg, uptake rates over 94%).…”

Preconception care and genetic risk: ethical issues

“…However, there may be some room for differentiation between PCS as a top-down initiative from the health care system (as in the case of the recently introduced obligatory offer of PCS for CF in the USA; ACOG 2011) and community-based initiatives targeting high profile genetic risks for serious diseases within that specific community or population. Whereas reduced birth rates of affected children should not be regarded as the measure of success of the former type of programmes, doing so may seem less problematic for programmes of the latter kind (Laberge et al 2010). The difference being that in programmes set up in answer to a need for prevention as self-defined by a community in which many families are struck by a high burden of disease, most participants will actively support the aim of bringing down the birth-prevalence of the disease, whereas this is less obvious in top-down programmes aimed at populations rather than communities.…”