Arrhythmia Variant Associations and Reclassifications in the eMERGE-III Sequencing Study
Authors: Glazer Andrew M. , Davogustto Giovanni , Shaffer Christian M. , Vanoye Carlos G. , Desai Reshma R. , Farber-Eger Eric H. , Dikilitas Ozan , Shang Ning , Pacheco Jennifer A. , Yang Tao , Muhammad Ayesha , Mosley Jonathan D. , Van Driest Sara L. , Wells Quinn S. , Shaffer Lauren Lee , Kalash Olivia R. , Wada Yuko , Bland Harris T. , Yoneda Zachary T. , Mitchell Devyn W. , Kroncke Brett M. , Kullo Iftikhar J. , Jarvik Gail P. , Gordon Adam S. , Larson Eric B. , Manolio Teri A. , Mirshahi Tooraj , Luo Jonathan Z. , Schaid Daniel , Namjou Bahram , Alsaied Tarek , Singh Rajbir , Singhal Ashutosh , Liu Cong , Weng Chunhua , Hripcsak George , Ralston James D. , McNally Elizabeth M. , Chung Wendy K. , Carrell David S. , Leppig Kathleen A. , Hakonarson Hakon , Sleiman Patrick , Sohn Sunghwan , Glessner Joseph ,   the eMERGE Network, Denny Joshua , Wei Wei-Qi , George Alfred L. , Shoemaker M. Benjamin , Roden Dan M. 
Published: December 2021

Background:
Sequencing Mendelian arrhythmia genes in individuals without an indication for arrhythmia genetic testing can identify carriers of pathogenic or likely pathogenic (P/LP) variants. However, the extent to which these variants are associated with clinically meaningful phenotypes before or after return of variant results is unclear. In addition, the majority of discovered variants are currently classified as variants of uncertain significance, limiting clinical actionability.

Methods:
The eMERGE-III study (Electronic Medical Records and Genomics Phase III) is a multicenter prospective cohort that included 21 846 participants without previous indication for cardiac genetic testing. Participants were sequenced for 109 Mendelian disease genes, including 10 linked to arrhythmia syndromes. Variant carriers were assessed with electronic health record–derived phenotypes and follow-up clinical examination. Selected variants of uncertain significance (n=50) were characterized in vitro with automated electrophysiology experiments in HEK293 cells.

Results:
As previously reported, 3.0% of participants had P/LP variants in the 109 genes. Herein, we report 120 participants (0.6%) with P/LP arrhythmia variants. Compared with noncarriers, arrhythmia P/LP carriers had a significantly higher burden of arrhythmia phenotypes in their electronic health records. Fifty-four participants had variant results returned. Nineteen of these 54 participants had inherited arrhythmia syndrome diagnoses (primarily long-QT syndrome), and 12 of these 19 diagnoses were made only after variant results were returned (0.05%). After in vitro functional evaluation of 50 variants of uncertain significance, we reclassified 11 variants: 3 to likely benign and 8 to P/LP.

Conclusions:
Genome sequencing in a large population without indication for arrhythmia genetic testing identified phenotype-positive carriers of variants in congenital arrhythmia syndrome disease genes. As the genomes of large numbers of people are sequenced, the disease risk from rare variants in arrhythmia genes can be assessed by integrating genomic screening, electronic health record phenotypes, and in vitro functional studies.

Registration:

URL:
https://www.clinicaltrials.gov
; Unique identifier; NCT03394859.