ITPA and myeloproliferative neoplasm: To gain insights, targeted sequencing was performed to detect myeloid‐associated mutations and SNPs in eight loci across three genes (IFNL4, IFN‐γ, and inosine triphosphate pyrophosphatase [ITPA]) to explore their predictive roles in our cohort of 21 ropeginterferon alpha‐2b (ROPEG)‐treated MPN patients, among whom real‐time quantitative PCR was also performed periodically to monitor the JAK2V617F allele burden in 19 JAK2V617F‐mutated cases.