JMML accounts for 1-2% of childhood leukemias each year; in the United States, an estimated 25-50 new cases are diagnosed each year, which also equates to about 3 cases per million children.  There is no known environmental cause for JMML.  Since about 10% of patients are diagnosed before 3 months of age, it is thought that JMML is a congenital condition in these infants.
Juvenile myelomonocytic leukemia epidemiology and demographics
T-cell prolymphocytic leukemia epidemiology and demographics
B-cell prolymphocytic leukemia epidemiology and demographics
Mast cell leukemia epidemiology and demographics
Acute lymphoblastic leukemia epidemiology and demographics
Hairy cell leukemia epidemiology and demographics
Angioimmunoblastic T-cell lymphoma epidemiology and demographics
Acute myeloid leukemia epidemiology and demographics