By anchoring different cell structures like Z-bands, mitochondria, and desmosomes to the cytoskeleton, desmin filaments are essential for cellular integrity, signal transduction and mitochondrial function. The spectrum of clinical phenotypes associated with DESgene mutations is wide and heterogeneous. The most common clinical presentations of desminopathy include cardiomyopathy, cardiac conduction disease, and progressive skeletal myopathy. We present a case of an 11-year-old girl with progressive dilated cardiomyopathy (DCM) needing ECMO treatment. ECMO treatment was complicated by the early development of intracardiac thrombi and lung necrosis. Post-mortem exome sequencing revealed the causative, previously unreported, de novomutation of DESgene, c.365 A > C, p.Tyr122Ser, characterized with unusually progressive clinical course leading to death.