Numerous GFAP(+)/MBP(+) cells are reported in a mouse model of phenylketonuria, which is associated with central hypo-mylination (Dyer et al., 1996), and there is strong evidence for astrocyte production from NG-2 cells following traumatic injury (Carmen et al., 2007), ischemia (Honsa et al., 2012) and spinal cord injury (Wu et al., 2005). Here, GFAP is linked to phenylketonuria.