RESUMEN
BACKGROUND: Heterozygous mutations in the transcription factor GATA2 result in a wide spectrum of clinical phenotypes, including monocytopenia and Mycobacterium avium complex (MAC) infection (MonoMAC) syndrome. Patients with MonoMAC syndrome typically are infected by disseminated nontuberculous mycobacteria, fungi, and human papillomavirus, exhibit pulmonary alveolar proteinosis during late adolescence or early adulthood, and manifest with decreased content of dendritic cells (DCs), monocytes, and B and natural killer (NK) cells. CASE PRESENTATION: A 39-year-old woman was diagnosed with MonoMAC syndrome postmortem. Although she was followed up based on the symptoms associated with leukocytopenia that was disguised as sarcoidosis with bone marrow involvement, she developed disseminated nontuberculous mycobacterial infection, fungemia, and MonoMAC syndrome after childbirth. Genetic testing revealed a heterozygous missense mutation in GATA2 (c.1114G > A, p.A372T). Immunohistochemistry and flow cytometry showed the disappearance of DCs and decreased frequency of NK cells in the bone marrow, respectively, after childbirth. CONCLUSIONS: To the best of our knowledge, this is the first study reporting that MonoMAC syndrome can be exacerbated after childbirth, and that immunohistochemistry of bone marrow sections to detect decreased DC content is useful to suspect MonoMAC syndrome.