CSF1R and juvenile xanthogranuloma: Several gene mutations have been linked to JXG, including MAP2K1, Colony Stimulating factor 1 receptor (CSF1R), ALK, MET, CSF3R, KRAS, NRAS, KIT (Tyrosine Kinase Receptor type III), JAK3 (Tyrosine protein kinase JAK3), and a number of gene fusions.