Genocopy of EVI1-AML with paraneoplastic diabetes insipidus: PRDM16 overexpression by t(1;2)(p36;p21) and enhancer hijacking.

Diabetes insipidus (DI) in patients with acute myeloid leukaemia (AML) and chromosome 3q alterations (EVI1/PRDM3/MECOM overexpression) constitutes a poorly understood paraneoplasia. A 44-year-old patient presented with clinical and morphological features of this syndrome but, surprisingly, disclosed the rare translocation t(1;2)(p36;p21), with massive PRDM16 overexpression. WGS and RNA sequencing suggest enhancer hijacking of the ZFP36L2 enhancer region as underlying mechanism. Methylome alterations were similar to those in EVI1/PRDM3/MECOM AML, indicating converging pathways. The patient was successfully allografted, she is in complete remission 14 months later. We conclude that t(1;2)(p36;p21), with massive PRDM16 overexpression, can result in a faithful genocopy of EVI1/PRDM3/MECOM AML, including DI.