Biological samples (blood and bone marrow samples).

This trial is a translational, open-label, multi-site, retrospective and prospective cohort study of 250 patients aiming to characterize predictive parameters of clonal evolution in a population of subjects carrying the germline GATA2 mutation. This study will be conducted on a population of subjects either with previous germline GATA2 mutation identified or newly identified for germline GATA2 mutation in the context of routine care. Prospective cohort: 150 subjects will be included in this interventional prospective cohort study: * Alive subjects previously identified with a germline GATA2 mutation through the already existing "Neutropenia database"; * Subject identified in the investigating centers in the context of a newly identified germline GATA2 mutation. For each included patient, biological samples (blood and bone marrow samples) will be collected at baseline visit and then during 5 years, according to the samples taken in the standard practice. No additional sampling will be performed for the study. Retrospective cohort: Subjects (100 cases in total) previously identified with germline GATA2 mutation through the already existing "Neutropenia database" and with the following features may enter the retrospective cohort: * Deceased patients, * Lost to follow-up patients. Clinical follow-up data will be obtained from this database and/or patient's medical report. For each retrospective case, archived blood and bone marrow samples (collected in a sanitary setting) will be sent to sponsor's centralized unit for analysis.