Germline mutations in PTPN11 gene cause Noonan syndrome and the clinically similar LEOPARD syndrome (LS). LS is a rare congenital developmental disorder characterized by multiple lentigines, cardiac abnormalities, facial dysmorphism, retardation of growth, and deafness. Mutations in exons 7 and 12 of the PTPN11 gene can be identified in nearly 90% of patients with LS. PTPN11 gene encodes for an ubiquitously expressed protein tyrosine phosphatase SHP-2 involved in a variety of intracellular signaling processes in development and hematopoiesis. Somatic PTPN11 mutations contribute to leukemogenesis in children with hematologic malignancies including juvenile myelomonocytic leukemia, acute lymphoblastic leukemia, acute myeloid leukemia, and myelodysplasia. Two cases of leukemia (acute myeloid leukemia) have been reported in children with LS. The authors describe for the first time a girl with genetically confirmed LEOPARD syndrome presenting with common acute lymphoblastic leukemia.
*Pediatric Hematology and Oncology Unit, Department of Pediatrics, HELIOS Klinikum Erfurt, Erfurt
†Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, University of Freiburg, Freiburg, Germany
Reprints: Daniela Laux, MD, Pediatric Hematology and Oncology Unit, Department of Pediatrics, HELIOS Klinikum Erfurt, Nordhäuserstr. 78, 99089 Erfurt, Germany (e-mail: firstname.lastname@example.org).
Received for publication September 28, 2007; accepted March 17, 2008