If for years the treatment strategy of leukemia and related disorders (LRDs, including acute leukemias and predisposition syndromes) has been based solely on whether the patient could receive or not intensive chemotherapy and transplantation, the advent of new targeted or less targeted drugs has led to the development of a growing number of new therapeutic approaches, very often offered to specific patient/disease subsets, justifying the generic term of 'precision medicine'. As an international leukemia center of excellence, THEMA, the French National Center for Precision Medicine in Leukemia (selected as IHUB-2 by the French National Agency for Research), is a care, research, transfer and education initiative located at the Saint-Louis Research Institute (IRSL) in Paris and devoted to precision medicine in leukemia in a real-life environment. The present non-interventional study (eTHEMA) is a pillar of the whole THEMA project. As a prerequisite for precision medicine, this program focuses on individual data collection, aiming to collect high-quality data not only in patients treated into prospective clinical trials, but in every THEMA patient with a special interest in outpatients' care and research. The primary objective of this non-interventional study is to describe the baseline characteristics planned treatments and outcomes of patients newly diagnosed with acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), high-risk myelodysplastic syndrome (MDS), or myeloproliferative neoplasm (MPN)-related myelofibrosis, when managed and treated according to standard diagnosis and care practices.