Acute lymphoblastic leukemia developing in a patient with Noonan syndrome harboring a PTPN11 germline mutation.

Noonan syndrome (NS) is a congenital genetic disorder characterized by certain facial features, short stature, and congenital heart disease. The disorder is caused by genetic alterations in the RAS/MAPK signal pathway. NS patients show a predisposition to malignancy; however, acute lymphoblastic leukemia (ALL) is rarely reported.