Table 14

Diagnostic criteria for JMML

JMML diagnostic criteria
I. Clinical and hematologic features (all 4 features mandatory)
 • PB monocyte count ≥1 × 109/L
 • Blast percentage in PB and BM <20%
 • Splenomegaly
 • Absence of Philadelphia chromosome (BCR/ABL1 rearrangement)
II. Genetic studies (1 finding sufficient)
 • Somatic mutation in PTPN11* or KRAS* or NRAS*
 • Clinical diagnosis of NF1 or NF1 mutation
 • Germ line CBL mutation and loss of heterozygosity of CBL
III. For patients without genetic features, besides the clinical and hematologic features listed under I, the following criteria must be fulfilled:
 • Monosomy 7 or any other chromosomal abnormality or at least 2 of the following criteria:
  • Hemoglobin F increased for age
  • Myeloid or erythroid precursors on PB smear
  • GM-CSF hypersensitivity in colony assay
  • Hyperphosphorylation of STAT5
  • Modified from Locatelli and Niemeyer25 with permission.

  • * Germ line mutations (indicating Noonan syndrome) need to be excluded.

  • Occasional cases with heterozygous splice site mutations.