BackgroundHaemophagocytic lymphohistiocytosis (HLH) is a syndrome that occurs in patients with severe systemic hyperinflammation. GATA binding protein 2 (GATA2) is a transcription factor and key component in haematopoiesis and stem cell biology.Case presentationThree patients with HLH, one with Mycobacterium avium infection, one with Epstein–Barr virus (EBV) infection, and one with Mycobacterium kansasii infection, were all subsequently found to have a defect in the GATA2 gene through genetic testing.ConclusionsGATA2 deficiency syndrome should be considered in patients with myelodysplastic syndrome, nontuberculous mycobacterium infection and HLH. In addition, the GATA2 gene variant may be a genetic defect that could be the cause of the primary HLH. However, further studies are needed to confirm the role of GATA2 pathogenic variants in the pathogenesis of HLH.