Histone‐lysine‐N‐methyltransferase‐rearranged (KMT2A‐r) acute leukemia, commonly known as mixed lineage leukemia (MLL), is a distinct subtype of acute leukemia marked by genetic abnormalities in the KMT2A gene (also known as ALL‐1, HRX, or HTRX). Here, KMT2A is linked to acute leukemia.