The most convincing evidence supporting a role for Rab18 in LD homeostasis comes from the observation of an accumulation of enlarged lipid droplets in fibroblasts from patients affected by Warburg Micro syndrome, a neurological syndrome caused by mutations in Rab18, in Rab3GAP1/Rab3GAP2, which works as a GEF for Rab18, or in TBC1D20, a Rab18 GTPase‐activating protein (GAP) (Handley et al, 2015). The gene discussed is RAB18; the disease is Warburg micro syndrome.