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.

Inclusion Criteria:

1. All subject, at any age, with a germline GATA2 mutation.
2. Patient followed in the center within a standard of care procedure or clinical trial.
3. Signed written informed consent. For minor patients: patient assent and legal guardian(s) written informed consent obtained before inclusion in the study and prior performance of any study-related procedure.
4. For French patients: patient affiliated to a Social Health Insurance.

Exclusion Criteria:

1. GATA2 somatic mutation.
2. Any psychological, familial, geographic or social situation, according to the judgment of investigator, potentially preventing the provision of informed consent or compliance to study procedure.
3. Person who has forfeited his/her freedom by administrative or legal award or who is under legal protection, with the exception of persons under curatorship who may be included in the study.