BCS1L and Bjornstad syndrome: To understand the genetic background and determine whether the prognosis of MLL-PTD is influenced by any additional genetic aberration, we comprehensively investigated the pathobiologically important genetic aberrations known to be involved in myeloid neoplasms including DNA methylation, chromatin modifiers, activating signaling, myeloid transcription factors, and tumor suppressors in a large cohort of patients with MLL-PTD associated AML.