The inflammatory mediators produced by infiltrating T cells and activated fibroblasts present in the orbit (e.g., TNF-α, IFN-γ, TGF-β, IL-1β, IGF-1, and PDGF) lead to increased glycosaminoglycan (GAG) synthesis of orbital fibroblasts; thus they contribute to the remodeling of the orbital tissue, which has a pivotal role in the pathogenesis of GO. The gene discussed is TGFB1; the disease is geroderma osteodysplastica.