Prenatal genetic carrier screening in the genomic age

The Society for Maternal-Fetal Medicine, American College of Obstetricians and Gynecologists (ACOG), and American College of Medical Genetics and Genomics (ACMG) held a workshop entitled "Prenatal Genetic Testing" on January 25, 2017 to address several questions arising from the increasing implementation of preconception and prenatal expanded carrier screening (ECS). ECS allows for identification of a greater number of genetic sequencing changes (not all of which cause disease) and simultaneous testing for an increased number of genetic conditions without limitation to specific ethnic groups. The workshop participants reached consensus on the following: ethnicity based testing cannot be completely abandoned in favor of panethnic ECS; the specific approach to screening should be a patient's choice and not driven solely by provider preference; organizations should work to develop a framework for vetting conditions that should be reported on ECS panels; compared with prenatal screening, preconception screening is ideal and, at this time, due to the costs and the need for timeliness associated with prenatal screening posttest counseling and testing, that when ECS is offered it should be presented as a preconception option; preconception and prenatal panels should be identical across the spectrum of patients, including those undergoing assisted reproduction; adult-onset conditions should not be included on ECS panels; partners should be offered next-generation sequencing to identify rare variants when the first partner screened is determined to be a carrier; re-screening in subsequent pregnancies is not indicated, despite the potential for expansion of carrier screening conditions and variants; and more education about ECS for providers and patients is necessary to implement prenatal carrier screening in a responsible way.