It is also reported that the amount of Ras-related nuclear protein (Ran), a low molecular weight G protein that plays an important role in active nuclear-cytoplasmic transport, is decreased in the nucleus of fibroblasts from HGPS patients, and the nuclear-cytoplasmic concentration gradient is disrupted (Kelley et al., 2011). The gene discussed is RAN; the disease is Hutchinson-Gilford progeria syndrome.