Increased Carrier Detection With Expanded Carrier Screening in Multiple Ancestries [7O]

Abstract

INTRODUCTION: While ACOG, ACMG and NSGC recommend reproductive carrier screening for cystic fibrosis (CF) and spinal muscular atrophy (SMA), there are no guidelines to date routinely recommending expanded carrier screening for all reproductive patients. We sought to assess, by ancestry, the proportion of additional individuals who would be identified via an expanded panel compared to CF/SMA alone. METHODS: We deduced the expected observation rate for CF and SMA based on published literature and our laboratory's detection rate for individuals of Hispanic, Caucasian, African American (AA), and Asian descent. We also reviewed observed detection rates for the same patient populations from a 180‐disorder expanded carrier screen completed over an 18 month period. RESULTS: Expanded carrier screening was performed on 2,468 self-reported Hispanic, 921 Caucasian, 339 AA, and 174 Asian individuals. Combining expected carrier frequencies for CF and SMA and observed frequencies for all other diseases on the expanded panel, 1 in 2 Caucasians and 1 in 5 individuals of other backgrounds would be expected to be positive. Compared with the expected carrier frequencies of CF and SMA alone, an expanded carrier screen increased the probability of identifying carriers by 10-, 7-, 9-, and 9-fold, respectively, for the four patient populations. CONCLUSION: Compared to testing for CF and SMA alone, an expanded carrier screen increased the probability of detecting a carrier for a disorder by 7- to 10-fold. Expanded carrier screening will identify a substantially greater number of carriers among various ancestries compared to testing according to current guidelines alone.