PTPN11 and juvenile xanthogranuloma: Furthermore, JXG can occur in the context of Noonan syndrome, a RASopathy caused by germline mutations in genes of the Ras/MAPK pathway, illustrated by a case of a 3-month-old female with a germline p.Y62D PTPN11 mutation presenting multiple JXG skin lesions.43 Coexistence of neurofibromatosis type 1, JXG, and JMML has also been reported.44