title: [Gene mutations and clinical characteristics in children with juvenile myelomonocytic leukemia].
abstract: OBJECTIVE
  To study gene mutations and clinical features in children with juvenile myelomonocytic leukemia (JMML).
  
  
  METHODS
  The clinical data of 14 children who were diagnosed with JMML and were examined for the detection of common gene mutations were retrospectively analyzed.
  
  
  RESULTS
  Eleven (79%) out of 14 cases were male, and 3 (21%) were female. The median age at diagnosis was 2.0 years (age range: 0.6-6.0 years). Among 14 cases, there were 4 cases (29%) with PTPN11 mutation, 3 cases (21%) with N-RAS mutation, 1 case (7%) with PTPN11 mutation and K-RAS mutation, and 6 cases (43%) without any mutation. All four cases in the PTPN11 mutation group were male, and their median age was 2.5 years; interval from onset to diagnosis was 1.0 month; the white blood cell (WBC) count and absolute monocytes in peripheral blood were significantly higher, while the platelet (PLT) count was lower, as compared with the other three groups; they were followed up, and 3 cases died and 1 case had a progressive disease. In the N-RAS mutation group, there were two male cases and one female case, and their median age was 2.0 years; interval from onset to diagnosis was 13.7 months; after follow-up, 2 cases died and 1 case did not have an obviously progressive disease.
  
  
  CONCLUSIONS
  PTPN11 mutation is the most common mutation in JMML. The cases with PTPN11 mutation often have higher WBC count and absolute monocytes in peripheral blood, a lower PLT count, and a rapid disease progression, and their clinical outcomes are poor. The cases with N-RAS mutation have a slow disease progression. The clinical characteristics of the patients with compound mutations are not sure because of the small number of cases, and further clinical observation is indispensable.
authors.affiliation: Diagnostic and Therapeutic Center of Children's Blood Disease, Institute of Hematology, Blood Disease Hospital, Chinese Academy of Medical Science, Tianjin 300020, China. xfzhu1981@126.com.
authors.forename: Wen-Yu
authors.initials: WY
authors.lastname: Yang
authors.forename: Xiao-Juan
authors.initials: XJ
authors.lastname: Chen
authors.forename: Shu-Chun
authors.initials: SC
authors.lastname: Wang
authors.forename: Ye
authors.initials: Y
authors.lastname: Guo
authors.forename: Tian-Feng
authors.initials: TF
authors.lastname: Liu
authors.forename: Li-Xian
authors.initials: LX
authors.lastname: Chang
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Xiao-Fan
authors.initials: XF
authors.lastname: Zhu
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D011905:Genes, ras; D006801:Humans; D007223:Infant; D054429:Leukemia, Myelomonocytic, Juvenile / Q000097:blood / Q000235:genetics*; D008297:Male; D009154:Mutation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000235:genetics*; D012189:Retrospective Studies
chemical_list: C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11