FGFR1 and encephalocraniocutaneous lipomatosis: FGFR1 N546K and K656E oncogenic variants have been reported in postzygotic mosaicism as the genetic cause of a rare neurocutaneous condition known as Encephalocraniocutaneous lipomatosis (ECCL) (Bennett et al, 2016); however neither variant has so far been reported in the germline, suggesting embryonic lethality.