Of note, encephalocraniocutaneous lipomatosis (ECCL) a sporadic neurocutaneous syndrome with features of disordered RAS-MAPK signaling, appears to be mediated in at least a subset of cases by these very FGFR1 mutations (in mosaic, somatic distribution) and also carries an increased risk of low-grade gliomas, again predominately of pilocytic astrocytoma histology [6, 8, 42, 54, 64]. This evidence concerns the gene FGFR1 and pilocytic astrocytoma.