RAB18 and Warburg micro syndrome: RAB18 is a protein with emerging roles in ER to Golgi retrograde trafficking and other cellular trafficking (Vazquez-Martinez et al., 2007; Dejgaard et al., 2008), and LOF mutations in RAB18 are associated with Warburg micro syndrome, establishing a critical role of RAB18 in eye and brain development and neurodegeneration (Bem et al., 2011).