Congenital Infections (e.g., Congenital Malaria, Toxoplasmosis, Rubella, Cytomegalovirus (CMV), and Herpes Simplex Virus (HSV)): These infections can cause hepatosplenomegaly and affect the bone marrow, leading to leukoerythroblastosis, which is characterized by the presence of immature white and red blood cells in the peripheral blood.

Hemoglobinopathies (e.g., Alpha-Thalassemia Major): These genetic disorders can lead to severe anemia, hepatosplenomegaly due to extramedullary hematopoiesis, and leukoerythroblastosis.
Osteopetrosis: A rare genetic disorder that affects the bones, causing them to become denser and harder. This can lead to bone marrow failure, hepatosplenomegaly, and leukoerythroblastosis.
Gaucher's Disease: A genetic disorder that leads to the accumulation of harmful substances within cells, causing hepatosplenomegaly and bone marrow involvement.

Leukemia (e.g., Acute Lymphoblastic Leukemia (ALL) or Acute Myeloid Leukemia (AML)): Although less common in infants, leukemia can present with hepatosplenomegaly and leukoerythroblastosis. Missing this diagnosis could be fatal.
Lymphoma: Though rare in infants, certain types of lymphoma can cause hepatosplenomegaly and affect the bone marrow.
Severe Congenital Anemias (e.g., Blackfan-Diamond Anemia): These conditions can lead to significant bone marrow failure and extramedullary hematopoiesis, resulting in hepatosplenomegaly and leukoerythroblastosis.

Niemann-Pick Disease: A group of genetic disorders that affect lipid metabolism, leading to accumulation of lipids in cells, which can cause hepatosplenomegaly.
Wolman Disease: A rare genetic disorder characterized by the deficiency of an enzyme that breaks down certain lipids, leading to their accumulation in various organs, including the liver and spleen.
Chediak-Higashi Syndrome: A rare genetic disorder that affects the immune system and can cause hepatosplenomegaly among other symptoms.