Detection of the JAK2S523L mutation in 2 patients. (A) Clinical features and cooccurring molecular alterations detected by Sanger and next-generation sequencing (NGS). (B) Conventional Sanger sequencing in peripheral blood and buccal swabs reveals a somatic point mutation at c.1568, which causes an amino acid change from TCA to TTA. (C) Detection of the JAK2S523L mutation by NGS of 54 myeloid neoplasm–associated genes using a targeted panel (TruSight Myeloid Sequencing Panel; Illumina). (D) Schematic illustration of JAK2 structure and the localization of the JAK2S523L mutation. BM, bone marrow; Hb, hemoglobin; Hct, hematocrit; NA, not applicable; plts, platelets; VAF, variant allele frequency.