Acute Lymphoblastic Leukemia in a Patient with Monomac Syndrome/GATA2 Haploinsufficiency
Authors: Koegel Ashley , Tubman Venee N. , Hofmann Inga 
Published: October 2019

Abstract
Background: Heterozygous germline mutations in GATA2 have been described in three distinct conditions: 1) familial myelodysplastic syndrome (MDS)/ acute myeloid leukemia (AML), 2) Emberger syndrome which is characterized by lymphedema, warts and predisposition to MDS/AML, 3) MonoMac syndrome which is comprised of atypical nontuberculous mycobacterial infection, monocyte, and B and natural killer cell lymphoid deficiency. It is now recognized that these conditions represent a spectrum of hematopoietic, lymphatic and immune system disorders due to GATA2 haplosinsufficiency. MDS/AML due to GATA2 mutation shows a unique histopathology with characteristic dysplasia and is often associated with monosomy 7. Although many patients with GATA2 haploinsufficiency are initially asymptomatic the majority of patients will ultimately experience a significant complication such as severe infections due to immunodeficiency, pulmonary alveolar proteinosis (PAP), thrombotic events, bone marrow failure, MDS and progression to AML. Allogenic hematopoietic stem cell transplant (HSCT) is the only curative treatment for patients with GATA2 haploinsufficiency and those who develop MDS/AML. Here we report a unique patient who presented with with acute lymphoblastic leukemia (ALL) and was later found to have classical features of MonoMAC syndrome and GATA2 haploinsufficiency.
Case Summary: A previously healthy 11 year-old girl presented with fever, cellulitis, and pancytopenia. Bone marrow biopsy and aspirate were diagnostic for B-precursor acute lymphoblastic leukemia (ALL) with associated monosomy 7 and the following karyotype: 45,XX,-7,del(9)(p13),del(10)(q24). She was treated on Dana Farber Cancer Institute (DFCI) Consortium ALL Protocol 05-001, achieving a morphological and cytogenetic remission. During induction, she developed necrotizing aspergillus pneumonia and molluscum contagiousum. Her planned course of therapy was abbreviated due to the development of restrictive lung disease associated with PAP and disseminated Mycobacterium kansasii infection. Serial off therapy bone marrow studies were obtained given poor count recovery and revealed significant morphologic dysplasia, most prominent in the megakaryocytes. These findings were reminiscent of those characteristically seen in patients with GATA2 haploinsufficiency. Her infectious complications, profound monocytopenia, PAP and bone marrow dysplasia raised concern for MonoMAC Syndrome. Sanger Sequencing of GATA2 revealed a point mutation in the regulatory enhancer region of intron 5 (c.1017+572C>T) confirming the diagnosis. More than 3 years following remission of ALL, she developed a bone marrow relapse with her initial clone. Given her diagnosis of GATA2 haploinsufficiency, HSCT was selected as consolidation therapy in second remission. She succumbed to complications of HSCT 4 months after transplantation.
Conclusion: Patients with GATA2 haploinsufficiency show a heterogeneous clinical presentation and are at high risk for MDS/AML often associated with monosomy 7. The development of ALL in association with GATA2 haploinsufficiency has not been described in the literature. Hematologist and oncologists should be aware that ALL may be associated with GATA2 haploinsufficiency and should be attuned to the clinical, laboratory and histopathologic features of the MonoMAC syndrome that would prompt additional testing and potentially alter treatment regimens. As allogenic HSCT is the only definitive therapy for patients with GATA2 mutation, consideration of immediate HSCT following induction of remission should be considered in patients with ALL and GATA2 haploinsufficiency. Further, as patients with GATA2 mutations can be asymptomatic, it is imperative to screen family members for GATA2 mutations and offer genetic counselling prior to consideration as potential bone marrow donors.

Disclosures
No relevant conflicts of interest to declare.