Expanded carrier screening for recessive disorders: review of the characteristics of current internet-based offers

Carrier screening allows identification of healthy prospective parents who are at risk of conceiving a child affected with a monogenic recessive disorder. Recently, expanded carrier screening (ECS), which can identify carriers of a large number of recessive disorders in the general population, has grown in popularity and is now widely accessible, primarily through commercial companies. We performed a review of internet-based ECS offers in January 2017 to investigate the characteristics of ECS tests currently available, such as the number and nature of conditions screened. We excluded ethnicity-based carrier screening initiatives, research-centered ECS pilot programs, and offers where test characteristics, such as the lists of included genes/disorders were unavailable. We identified fifteen providers of ECS tests: 12 commercial companies, two medical hospitals and one academic medical center. The majority (12) of the providers were based in the USA, with the remaining three located in the Netherlands, Spain, and South Korea. We observed drastic differences in the characteristics of ECS tests, with the number of conditions ranging from 41 to 1700. Only three conditions (Cystic fibrosis, Maple syrup urine disease 1b, and Niemann-Pick disease) were screened for by all providers. Where the same disease gene was analyzed by multiple providers, substantial differences existed in the mutations included and/or variant interpretation methodologies. Given the importance of carrier screening results in reproductive decision-making, the observed heterogeneity across ECS panels is concerning. Efforts should be made to ensure that clear and concrete clinical criteria are in place to help inform the development of ECS panels.status: publishe