Distinct mutation features and its clinical significance in myelodysplastic syndromes with normal karyotype

Myelodysplastic syndromes (MDS) is a highly heterogeneous myeloid neoplastic disease, which needs personalized evaluation and therapy. To analyze the features and significance of gene mutations for MDS patients with normal karyotype (NK) at diagnosis, targeted sequencing was conducted on 616 MDS patients with NK, alongside 457 MDS cases with abnormal karyotype (AK). The results showed that the incidence of somatic mutation reached 70.3% and 83.8% in the NK and AK group, respectively. Initial mutation including ASXL1, DNMT3A and TET2 were common in NK group, which is the same as AK group. Some karyotype-associated gene mutations, such as TP53 and U2AF1, were relatively rare in NK group. Moreover, 34 out of 91 samples who progressed to acute myeloid leukemia (AML) underwent repeat sequencing during follow-up. 25 cases were checked out with newly emerged mutations. The AML-associated genetic alterations mainly involved with active signaling and transcription factors. In patients with NK, serial targeted sequencing was employed for minimal residual disease (MRD) monitoring, indicating the efficacy and relapse of the patients. In summary, MDS with NK showed distinct mutation features from those with AK. High-frequency gene mutations together with the mutational evolution suggested the diagnostic and monitoring significance of next generation sequencing for NK-MDS.