[Mutation analysis of 77 patients with normal-karyotype myelodysplastic syndrome]

To carry out mutation analysis for patients with myelodysplastic syndromes (MDS) and a normal karyotype.

Targeted capture and next-generation sequencing (NGS) was carried out using a customized 49-gene panel. FLT3 internal tandem duplication (FLT3-ITD), CALR, NPM1 and CEBPA mutations were detected by PCR and Sanger sequencing.

Sixty-two patients (80.5%) were found to harbor at least one mutation. Each patient has carried 2.21 mutations in average. Coexistence of ≥ 3 mutations was common (43.7%). The most commonly mutated genes were RUNX1 (23.4%, 18/77), ASXL1 (18.2%, 14/77), NPM1 (15.6%, 12/77), U2AF1 (15.6%, 12/77), DNMT3A (11.7%, 9/77). Patients with SF3B1 mutations were significantly older than those with ASXL1 mutations (P=0.023). Mutations of the DNMT3A gene were significantly associated with the blood platelet level compared with BCOR mutations (P=0.02). No significant difference was found in the number and rate of mutations between those under or above 60-year-old. Among 67 patients with clinical follow-up, 20 (29.8%) has transformed to acute myeloid leukemia, and the time of transformation has ranged from 1 to 44 months, with a average of 5.3 months. RUNX1, U2AF1 and FLT3 mutations are associated with leukemic transformation.

Coexistence of ≥ 3 mutations are frequent among patients with normal-karyotype MDS. Certain mutations are associated with age and leukemic transformation.