The analysis reviewed clinical data and samples from patients with MPN diagnosed at the authors’ center from 2018 to 2025 to characterize the prevalence and impact of JAK2G127D mutations. Next-generation sequencing was used to detect genetic mutations in samples, and cell models were used to evaluate the functional impact of co-occurring mutations. Out of 249 samples positive for JAK2V617F mutations, 15 carried a concurrent JAK2G127D mutation. Notably, JAK2G127D mutations only co-occured with JAK2V617F mutations. 

The analysis included 418 patients diagnosed with MF between January 2018 and January 2026 at 21 European centers. At time of diagnosis, 232 patients (55%) had proliferative MF and 186 (45%) had cytopenic MF, including 115 with moderate anemia, 41 with severe anemia, and 30 with leukopenia, thrombocytopenia, or combined cytopenias.