More than just mild thrombocytopenia: Clinical clues in the diagnosis of germline predisposition to malignancy from a rare ETV6 variant

Key Clinical MessageIn the evaluation of patients with longstanding mild thrombocytopenia, emphasis on family history, genetic testing, and collaborative clinical and laboratory-based family studies can ensure proper diagnosis and monitoring for malignancies. We report the diagnostic approach to mild and non-specific thrombocytopenia with unclear genetic findings in two sisters. Genetic sequencing revealed a rare variant in ETS Variant Transcription Factor 6, which is associated with inherited thrombocytopenia with predisposition to hematologic malignancy. Familial studies provided sufficient evidence for a likely pathogenic classification.