GTPase NRas (NRas) binds GDP/GTP and possess intrinsic GTPase activity. Alternate between an inactive form bound to GDP and an active form bound to GTP. Activated by a guanine nucleotide-e, Xenopus/Amphibian,change factor (GEF) and inactivated by a GTPase-activating protein (GAP). Defects in NRAS are a cause of juvenile myelomonocytic leukemia (JMML). JMML is a pediatric myelodysplastic syndrome that constitutes appro, Xenopus/Amphibian,imately 30% of childhood cases of myelodysplastic syndrome (MDS) and 2% of leukemia.