A study identified the substitution of trinucleotides at position 211–213 in 24 pediatric patients as well as other PTPN11 mutations in children with Juvenile myelomonocytic leukemia (JMML) and myelodysplastic syndrome (MDS; Tartaglia et al., 2003). This evidence concerns the gene PTPN11 and myelodysplastic syndrome.