Benefits of Expanded Carrier Screening
When it comes to carrier screening for single-gene disorders in prospective parents, the standard of care for decades has been to check carrier status for a limited set of disorders. These diseases have typically been selected based on family history or an increased frequency of mutation within a specific racial or ethnic group. Prospective parents also now undergo universal screening for cystic fibrosis.
The retrospective study included 346,790 prospective parents who were tested to see whether they carried genes for 95 severe conditionswhich, left untreated in their offspring, would cause intellectual disability or a much-shortened lifespanor in some profound cases, both.1
Results. Among 15 U.S. racial and ethnic categories, the calculated frequency of fetuses potentially affected by a profound or severe condition ranged from 94.5 per 100,000 for Hispanic couples to 392.2 per 100,000 for Ashkenazi Jewish couples.
For most racial and ethnic groups, expanded carrier screening identified more disease risks than screening based on current guidelines. For example, for Northern European couples, the standard screening panels predicted55.2 hypothetical fetuses affected per 100,000, while expanded carrier screening identified nearly 3 times this number.
Recommendations. Expanded carrier screening can clearly increase the detection of carrier status for a variety of serious genetic conditions. However, the researchers recommend prospective studies comparing standard carrier screening with expanded carrier screening in at-risk populations before recommending widespread adoption of expanded screening.
1. Haque IS et al. JAMA.2016;316(7):734742.