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Original Investigation
November 5, 2018

Clinical Utility of Reinterpreting Previously Reported Genomic Epilepsy Test Results for Pediatric Patients

Author Affiliations
  • 1Department of Pathology, University of Texas Southwestern Medical Center, Dallas
  • 2Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas
  • 3Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas
  • 4Eugene McDermott Center for Human Growth & Development, University of Texas Southwestern Medical Center, Dallas
  • 5Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
JAMA Pediatr. Published online November 5, 2018. doi:10.1001/jamapediatrics.2018.2302
Key Points

Question  How often do genomic test result interpretations change?

Findings  In this study of reported genetic variants from clinical genomic epilepsy tests, 67 of 185 pediatric patients (36.2%) had variants reclassified. A clinically significant change in the interpretation occurred in 19 of 61 patients (31.1%) with a genetic diagnosis during the 5-year study.

Meaning  The findings of this study suggest that pediatric patients with epilepsy and previous genomic test results should have their test results reinterpreted at least every 2 years and before further genetic testing.

Abstract

Importance  Clinical genomic tests that examine the DNA sequence of large numbers of genes are commonly used in the diagnosis and management of epilepsy in pediatric patients. The permanence of genomic test result interpretations is not known.

Objective  To investigate the value of reinterpreting previously reported genomic test results.

Design, Setting, and Participants  This study retrospectively reviewed and reinterpreted genomic test results from July 1, 2012, to August 31, 2015, for pediatric patients who previously underwent genomic epilepsy testing at a single tertiary care pediatric health care facility. Reinterpretation of previously reported variants was conducted in May 2017.

Main Outcomes and Measures  Patient reports from clinical genomic epilepsy tests were reviewed, and all reported genetic variants were reinterpreted using 2015 consensus standards and guidelines for interpreting hereditary genetic variants. Three classification tiers were used in the reinterpretation: pathogenic or likely pathogenic variant, variant of uncertain significance (VUS), or benign or likely benign variant.

Results  A total of 309 patients had genomic epilepsy tests performed (mean [SD] age, 5.6 [0.8] years; 163 [52.8%] male), and 185 patients had a genetic variant reported. The reported variants resulted in 61 patients with and 124 patients without a genetic diagnosis (VUS variants only). On reinterpretation of all reported variants, 67 of the 185 patients (36.2%) had a change in variant classification. Of the 67 patients with a genetic variant change in interpretation, 21 (31.3%) experienced a change in diagnosis. During the 5 years of the study, 19 of 61 patients (31.1%) with a genetic diagnosis and 48 of 124 patients (38.7%) with undiagnosed conditions (VUS only) had their results reclassified. Review of genomic reports issued during the final 2 years of the study identified reclassification of variants in 4 of 16 patients (25.0%) with a pathogenic or likely pathogenic variant and 11 of 41 patients (26.8%) with a VUS.

Conclusions and Relevance  The identified high rate of reinterpretation in this study suggests that interpretation of genomic test results has rapidly evolved during the past 5 years. These findings suggest that reinterpretation of genomic test results should be performed at least every 2 years.

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