The diagnostic utility of targeted gene panel sequencing in discriminating etiologies of cytopenia

Gang Zheng, Ping Chen, Aparna Pallavajjalla, Lisa Haley, Lukasz Gondek, Amy Dezern, Hua Ling, Federico De Marchi, Ming Tseh Lin, Christopher Gocke

Research output: Contribution to journalArticlepeer-review

Abstract

The diagnostic utility of somatic mutations in the context of cytopenias is unclear: clonal hematopoiesis can be found in healthy individuals, patients with aplastic anemia (AA), clonal cytopenia of undetermined significance (CCUS) and myelodysplastic syndrome (MDS). We examined a cohort of 207 well-characterized cytopenic patients with a 640-gene next generation sequencing (NGS) panel and compared its diagnostic utility with a “virtual” 41 gene panel. The TET2, SF3B1, ASXL1, and TP53 were the most commonly mutated genes (frequency > 10%). Mutations in the 640-gene panel show high sensitivity (98.3%) but low specificity (47.6%) for diagnosis of MDS. Notably, mutations of splicing factors and genes in the RAS pathway are relatively specific to MDS. Furthermore, high variant allele frequency (VAF) predicts MDS: when the VAF is set at 20%, the positive predictive value (PPV) for MDS is 95.9%, with a specificity of 95.3%. The presence of two or more somatic mutations with ≥10% VAF showed a PPV of 95.2%. While the “virtual” 41-gene panel showed a mild decrease in sensitivity (95.7% vs 98.3%), 100% specificity was observed when either VAF was set at ≥20% (100% vs 95.3%), or two or more somatic mutations had VAFs ≥ 10%. Our study shows targeted gene panel sequencing improves the diagnostic approach and accuracy for unexplained cytopenia, with its high sensitivity and high PPV for MDS when applying VAF cutoffs. Furthermore, a 41-gene panel was shown to have at least comparable performance characteristics to the large 640-gene panel.

Original languageEnglish (US)
Pages (from-to)1141-1148
Number of pages8
JournalAmerican journal of hematology
Volume94
Issue number10
DOIs
StatePublished - Oct 1 2019

ASJC Scopus subject areas

  • Hematology

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