Advertisement

Diagnostic high-throughput sequencing of 2,396 patients with bleeding, thrombotic and platelet disorders

Kate Downes, Karyn Megy, Daniel Duarte, Minka Vries, Johanna Gebhart, Stefanie Hofer, Olga Shamardina, Sri V V Deevi, Jonathan Stephens, Rutendo Mapeta, Salih Tuna, Namir Al Hasso, Martin W. Besser, Nichola Cooper, Louise Daugherty, Nick Gleadall, Daniel Greene, Matthias Haimel, Howard Martin, Sofia Papadia, Shoshana Revel-Vilk, Suthesh Sivapalaratnam, Emily Symington, Will Thomas, Chantal Thys, Alexander Tolios, Christopher J. Penkett, Willem H. Ouwehand, Stephen Abbs, Michael A. Laffan, Ernest Turro, Ilenia Simeoni, Andrew D. Mumford, Yvonne M. C. Henskens, Ingrid Pabinger, Keith Gomez and Kathleen Freson

Key Points

  • ThromboGenomics HTS test validates recent gene discoveries and detects copy number and intronic variants.

  • ThromboGenomics reveals a molecular diagnosis for 37.3% of 2,396 patients with bleeding, thrombotic and platelet disorders.

Abstract

A targeted high-throughput sequencing (HTS) panel test for clinical diagnostics requires careful consideration of the inclusion of appropriate diagnostic-grade genes, the ability to detect multiple types of genomic variation with high levels of analytic sensitivity and reproducibility, and variant interpretation by a multi-disciplinary team (MDT) in the context of the clinical phenotype. We have sequenced 2,396 index patients using the ThromboGenomics HTS panel test of diagnostic-grade genes known to harbour variants associated with rare bleeding, thrombotic or platelet disorders (BTPD). The molecular diagnostic rate was determined by the clinical phenotype, with an overall rate of 49.2% for all thrombotic, coagulation, platelet count and function disorder patients and a rate of 3.2% for patients with unexplained bleeding disorders characterized by normal hemostasis test results. The MDT classified 745 unique variants, including copy number and intronic variants, as Pathogenic, Likely Pathogenic or Variants of Uncertain Significance. Half (50.9%) of these variants are novel and 41 unique variants were identified in 7 genes recently found to be implicated in BTPD. Inspection of canonical hemostasis pathways identified 29 patients with evidence of oligogenic inheritance. A molecular diagnosis has been reported for 894 index patients providing evidence that introducing an HTS genetic test is a valuable addition to laboratory diagnostics in patients with a high likelihood of having an inherited BTPD.

  • Submitted December 11, 2018.
  • Revision received April 29, 2019.
  • Accepted April 22, 2019.