Mice deficient for Ercc6 or Ercc8 have been generated and used to mimic mild CS symptoms, including fat tissue reduction, photoreceptor cell loss, and mild but characteristic nervous system pathology (van der Horst et al., 1997, 2002; Gorgels et al., 2007; Jaarsma et al., 2011). Here, ERCC8 is linked to Cowden syndrome 1.